?? Answers

  • Install app latest version with Ubuntu Snap

    I want to install application most recent version on Ubuntu. With this command snap refresh , but it doesn’t work.

    Getting a ‘snap “<app name>” has no updates available’ message instead.

    There is a higher version from snap info <app name> for example below.

    channels:
      latest/stable:    12.5 2021-09-23 (50) 516MB classic
      latest/candidate: ↑                          
      latest/beta:      ↑                          
      latest/edge:      12.5 2021-09-19 (50) 516MB classic
      12.0/stable:      12.0 2020-06-12 (30) 462MB classic
      12.0/candidate:   ↑                          
      12.0/beta:        ↑                          
      12.0/edge:        ↑                          
      11.0/stable:      11.0 2019-09-04  (6) 399MB classic
      11.0/candidate:   ↑                          
      11.0/beta:        ↑                          
      11.0/edge:        ↑       
    

    What I need do to force the update to latest version?

    ANSWER

    If you look at the “tracking” value after the snap info command, you will see the channel the app is currently on.

    That’s the same channel listed in the “channels” information. To get that latest version you want, change the channel accordingly. Let us say you are at 12.0/stable now. You want to download and update to 12.5. That means you need to change to latest/stable channel in this case.

    For that we will need to add an option that is --channel= to change the target channel.

    The command it will look like this in the terminal:

    :~$ snap refresh  --channel=latest/stable

    This will immediately begin the download process to update to that version of that channel specified.

    Add sudo optionally. Optional because Ubuntu will prompt you for your password if you don’t. A pop-up dialog window will appear for you to enter the password.

  • A way to stream Netflix in Nintendo Switch?

    Is there a way to install custom app that can play Netflix on my Nintendo Switch, much like those unverified sources installation approach on Android?

    I read there is easier way through “secret browser” to play Netflix. But many comments say it does nt work.

    ANSWER

    Short answer is – NO / None / Nada.

    Unless, you install Android on or jailbreak it. The former means you’ll be technically booting to Android system. The latter is much more like what you probably have heard of people jailbreaking their iPhones, then run apps that were not supposed to be playable on the device.

    Both are risky. It can cause irreversible damage to your Nintendo Switch. And you’ll end up with what they popularly call as a bricked device. Just an expensive paperweight on other words. The choice is yours. Read and understand thoroughly before you decide to go ahead. If you like to tinker then this should be a fun exercise.

    The other claim that you can “play Netflix” on a browser on the Nintendo Switch without doing anything overly technical is only half true. Yes there is that so called secret browser that you can force to show and use much like you would a browser on your Mac or phone. It involves manually setting an IPv4 address as DNS in your Switch’s Internet connection settings.

    While you can logon to a Netflix account or browse the catalog, that’s about all you can do there. When you start playing a movie Netflix will say the browser does not support the minimum requirements for streaming the content.

    So you are left with a browser, that is awkward and clunky to use.

    Don’t bother!

    Get a tablet instead if you want a portable device for watching movies on the go.

  • Identify Songs Playing Using Smartphone

    What nice and safe apps are there that I can install on iPhone or Android to identify songs playing from another source? Preferable to have no ads, unlimited use and free of charge.

    ANSWER

    A few years back when I was in that apps discovery phase on my Android and installing as many as I can even when those apps would hardly ever be used after the first try, I came upon Shazam. Was impressed by it. It was able to ID the songs quite accurately. It sometimes took a while, a few longer seconds, sometimes but it normally was able to pick up and tell me the song title and artist. The sound quality it is listening to also is a factor for proper identification. It did have some success on getting the songs right in a public place, like a bar or a cafe, where music was playing loudly and a lot of other noise around.

    There are many sound discovery or music recognition apps out there for both Android and iPhone. I have heard of SoundHound or Musixmatch.

    I have not used such apps for a long time. Shazam was free when it came out. No ads then. I might have installed it again years after, and as I recall the UI changed this time with ads too. But I could be wrong. It might have been a different app. SoundHound, Musixmatch and Shazam come with free and paid versions. Whether these apps have limited use for free versions, you can find that out or DON’T.

    Try out those 3 apps, OR you don’t really have to go to all the trouble. Google Assistant on Android can do the same magic. Just ask it, “Which song is this?”. Type it or say it. Better the latter. I have done it several times, for example while driving and listening to a local FM radio station.

    Apple’s Siri can do the same.

  • Getting an MYSQLDump error

    I upgrade MySQL DB from 5.6 to 5.7 version not too long now with no issues happened after. But at that time I did not use mysqldump command. Now I tried to backup the database and gettting this error message:

    mysqldump: Error: ‘Access denied; you need (at least one of) the PROCESS privilege(s) for this operation’ when trying to dump tablespaces

    How to fix this error.

    ANSWER

    The PROCESS privilege requirement was added only in MySQL version 5.7.31. This is an expected behavior and affects mysqldump utility. There is a report here and some discussions –

    https://bugs.mysql.com/bug.php?id=100219

    If your user has no admin privilege to the MySQL database, the quick workaround is to add the –no-tablespaces option. The usage like below.

    mysqldump --no-tablespaces -u user -p DB_NAME > BACKUP_FILE.sql

    On the other hand, if you have admin access, then grant that user the PROCESS privilege like this:

    GRANT PROCESS ON *.* TO user@localhost;

    Be warned that such privilege is usually reserved for server administrator users. It works on a global context, so it cannot be specified on a per database approach. Granting just any user this PROCESS privilege is not a good idea. It may cause “data leaks” when sensitive queries gets exposed because this privilege can allow a user to see queries being executed in active sessions. This becomes more critical when the server instance is shared.

  • Accidentally deleted all in Git branch

    HELP! What to do?

    I made first commit. Noticed a file that is not supposed to be save with sensitive values. Did not want to get the history for this one file in there, that would be viewable still.

    Proceed to revert that first commit, thinking it will go back when no files was committed.

    All files are gone now as result! I cannot find in my project folder even recycle bin.

    ANSWER

    First commit? But you want to undo for a file or two? Easy peasy. No need for revert. It’s only 1 commit! Then you would not have been in this trouble you are now.

    Delete the .git folder! Mind you this is before you should have done any git voodoo. Re-init git, add files, then commit. Then you’re done. You’re back in business without having so much down time.

    Now going to the other solution. I have encountered this before like you. The files are still there. So to speak. Git knows it, since it has the history for that action. A simple git log will prove.

    Normally, you can pick the files back one by one simply by using the checkout command. But first, get a list of these files, including full path to it. This will show all the files that have been affected or deleted in your case.

    git status

    THEN

    git checkout path/to/filename

    For a few files, this approach works. Not very convenient when you have dozens to hundreds of files to recover. This may be your situation too. For some reason, using a wildcard will not work.

    git checkout *
    git checkout path/to/*

    It executes but does nothing.

    Sometimes commands like below will do the trick. Or it won’t. YMMV. But may be limited to *NIX-compatible OSes. For Windows, use Git Bash for one.

    git ls-files -d | xargs git checkout --
    

    In my experience, I did the following steps in git.

    git log
    git checkout COMMIT_ID
    git commit -m "Restore my files"
    git checkout master

    The first command is to get the commit ID.

    Second is to checkout at that commit. Now you’ll be in limbo. You’re not back at master branch where you started out. Instead this checkout will be outside of master. You’ll see a message such as

    HEAD detached at COMMIT_ID_SHORTENED
    

    This is all good. Don’t worry. Just commit those files again. That’s the third command up there.

    Then once done, checkout to master. The last command shown up there.

    If for some reason there are files that conflict, the switch to master branch won’t succeed. Just add those conflicting files too.

    git add path/to/file/name
    git commit -m "Some more files"
    git checkout master

    Now all is good. Look at your folder. All files are there again.

  • Auto-create MySQL Database in Java

    Many Java / JDBC / JPA examples show only how to create DB table(s) if not existing. Like putting the table defintion or DDL in a .sql file, where the program can pick it up and execute on run-time.

    But not with the database itself.

    How can database be created on the fly?

    ANSWER

    With JDBC this can be done as a parameter to the URL connection string.

    In the example shown below –

    datasource.url=jdbc:mysql://localhost:3306/SCHEMA_NAME?createDatabaseIfNotExist=true

    The parameter (comes after ?) – createDatabaseIfNotExist – must be set at value of true.

    As I recall, this works only after MySQL version 5.1.

    Note: SCHEMA is MySQL speak for database. It is common to call that even with other products. Other databases or code implementations may also term it as CATALOG.

  • Create Fat .gitignore in Intellij

    Rather than create my .gitignore file by hand or copy from a previous project, I do not prefer this method. Is there a quicker way to generate the .gitignore file with many of the things I don’t want to be tracked by Git to be included in it.

    ANSWER

    Intellij IDEA

    Plugin: https://plugins.jetbrains.com/plugin/7495–ignore/

    Add that to your Intellij IDEA app. There is a button in that page to automatically download and install this plugin. Make sure the Intellij app is running before hitting that button.

    Or you could simply download, then install manually. Select the Versions tab in the plugin page. Choose the version you want to download. Find the zipped file in your “downloads” folder.

    To install manually, head over to: Settings > Plugins > (gear icon) > Install Plugin from Disk

    The gear icon might be different with other versions of IntelliJ.

    The plugin should be activated already, not needing an app restart.

    Eclipse

    For Eclipse, I’m not sure of a plugin that has pre-defined lists. I can right click on a folder/file and add to .gitignore (Team > Ignore), is what I did before. Haven’t tried an Eclipse Marketplace search.

    Visual Studio Code (VS Code)

    Click extension then type in “gitignore” in the search box. Look for the extension by CodeZombie. Versions as of this writing is 0.7.0.

    To use, do the following:

    Start command palette (with Ctrl+Shift+P or F1) and start typing Add gitignore

    Other

    Another way is to go to gitignore.io OR github.com/github/gitignore and get a generated .gitignore template from there. Search/select the application, OS you want. Then copy/download the generated templates.

  • Fatal: Refusing to Merge Unrelated Histories
    fatal: refusing to merge unrelated histories

    I get this error every now and then. This happens when I created a new branch first right after a new Git project was started (by me), without bothering to base it from the Master branch. The reason is the lack of permission/access to being able to write or put anything on the latter branch.

    Rather than waiting for someone to kick off the Master branch, I just go ahead and start my own branch as I’ve mentioned earlier. Later on, somebody from the team who has write permissions to Master, starts a README file just to initiate it. Thus the “unrelated histories” issue happens from then on. Two branches that started off independently from each other and with no common base.

    The issue appears when I want to merge my branch to Master. Git will say my branch is behind on commit on the branch it will be merged into. If I try to merge it, it gets rejected. The pipeline also won’t allow for merge conflicts like this, and advises me to fix it first.

    ANSWER

    As I recall, this behavior started after a certain Git version only. This to avoid to unnecessarily create a parallel history being merged into the project, because a previous merge happened between to branches that didn’t have a common base.

    I’ve used Git’s “–allow-unrelated-histories” option to fix this problem. I’ll do this via command line.

    Pull the Master branch into mine with the option above included.

    Fix the merging conflict.

    Commit the changes.

    Push to remote repository.

    Then this time the merge request to Master will not warn that my branch is behind a commit.

    Others have commented saying that rebasing also does the trick for them. I do not recall having gone that route though.

  • What Password Managers available in Linux

    List of Password Managers that are available in Linux?

    Aside from BitWarden. I want to know some alternatives you guys are using. Prefer it’s standalone program instead of browser plugin or extensions.

    ANSWER

    I am using KeePassXC personally for some time. 1Password for work-related stuffs.

    The first one is a KeePass variant and open-source. It has a Qt-based application that has been available for Linux for a while. Then, 1Password support in Linux was in beta since last year. Recently it has been moved out of beta.

    Others I know off the top of my head,

    • AuthPass
    • Password Safe (for Gnome DE)
    • KeePassX (where KeePassXC was forked)

  • View what’s inside the Keystore

    I have a file with java keystore type that I would like to inspect. Can the contents of the keystore of java be viewed if I don’t have it password? I want to verify an SSL certificate is inside of it. Maybe also check the details are correct, expiration date and so on. What tool can be used to open the keystore?

    ANSWER

    The normal notion that because the Java Keystore (JKS for short) asks for a password, then I cannot see what is in it is not entirely correct. The password for the JKS does not prevent that. Instead the purpose of the password is to protect the integrity of the JKS. The intention is that without the password, I should not be able to modify the contents, such as adding certificates or deleting some.

    With the proper tool I can still read what is inside of a JKS. Normally we just use the keytool. This command line tool usually comes with the Java installation in your system. Try to find it in the installation directory of Java. It resides together with other Java binaries in the ../bin/ directory.

    Without password warnings will be displayed, like this one:

    *****************  WARNING WARNING WARNING  *****************
    * The integrity of the information stored in your keystore  *
    * has NOT been verified!  In order to verify its integrity, *
    * you must provide your keystore password.                  *
    *****************  WARNING WARNING WARNING  *****************
    

    How to print what is inside the JKS:

    (1) View all as a list

    :~$ keytool -list -keystore /path/to/keystore/file

    (2) View all as a list with details

    :~$ keytool -list -v -keystore /path/to/keystore/file

    (3) View a specific entry only using alias with details (The alias is the text that comes out in command #1 before the date, without the comma)

    :~$ keytool -list -alias "the alias text" -v -keystore /path/to/keystore/file
  • How to fix error: snap “telegram-desktop” has “install-snap” change in progress

    I enconter this error message when installing a Snap app Telegram for Desktop from the terminal command line. I followed instructions on how to do this from the Install button of the snapcraft.io website.

    First one I select is use the GUI app store. But nothing happens when click install button. Installing progress starts but go back to install. Click again and same thing is happens.

    When using the command line that is I got the error of:

    error: snap "telegram-desktop" has "install-snap" change in progress

    How to fix?

    ANSWER

    The error is because you are telling Snap to install an app that has already been scheduled for installation. It’s in the queue. The GUI app store is not very informative about this scenario. Hence, it will seem like the installation process failed when in fact that is not the case.

    My guess is it is put on schedule for installation because a higher priority install needs to be done first, most likely Snap core updates that have not yet been applied to the system yet.

    Either wait for the core updates to finish and wait for Telegram to get installed after, or force it to update right away.

    At the command line, do:

    :~$ snap changes

    It will show something such as:

    ID Status Spawn Ready Summary
    101 Done yesterday at 20:33 PST yesterday at 20:34 PST Auto-refresh snap "intellij-idea-community"
    102 Doing today at 11:36 PST - Install "slack" snap

    Abort the scheduled install for the app listed there, in your case “telegram-desktop” snap using the following command:

    :~$ sudo snap abort 102

    In the example above, I chose to abort install scheduled with ID 102. Choose the ID of the app you are trying to install that you will see on your terminal after the command above.

    Then install the snap app manually:

    :~$ sudo snap install telegram-desktop

    This should force snap to go ahead with the install, but first it may start with its core updates, followed by the telegram-desktop snap app.

  • Change default app to open torrent magnet link

    I installed a Popcorn-time desktop software on my Ubuntu linux to try that out. It appears to use a torrent technology to stream content as it downloads at the same time. Somehow that now gets the default to open magnet links for torrent files. Have not remembered any setting asking me to make the app open by default during installation or at download.

    I don’t want this, don’t know how to change to my default torrent software – Transmission BitTorrent.

    How to change back?

    ANSWER

    Add/edit it into the following files. Either or both is fine, but better to have it in for the system-wide list if you have multiple users.

    • System-wide: /usr/share/applications/defaults.list
    • User-specific: ~/.local/share/applications/mimeapps.list

    The value of this entry – x-scheme-handler/magnet – needs to be set to the application you prefer.

    For example, since you want it to be Transmission it will be similar as shown below:

    
    x-scheme-handler/magnet=transmission-gtk.desktop

    Just make sure the .desktop file for the desired application is correct. Again you can check for that file in the same directory where this list is found.

    As an alternative, the following terminal commands will also help.

    Find out what is the existing default app that will handle such mime-type for your existing user:

    :~$ xdg-mime query default x-scheme-handler/magnet

    Replace that by using the next command:

    :-$ xdg-mime default transmission-gtk.desktop x-scheme-handler/magnet

    Lastly, you can check again if the last command was successful by running the first one.

  • Base64-encoded value is slightly different at the end of string

    Why is there slight differences in base64 encoding at the end of the encoded string. It could be one or more of characters that’s different.

    Here an example done on base64encode.org using this text – Hey, Diddle Diddle – the output value is:

    SGV5LCBEaWRkbGUgRGlkZGxl

    But when I do same in base64 command line, I get this instead:

    SGV5LCBEaWRkbGUgRGlkZGxlCg==

    It is 4 more characters longer. Which one is correct encoding?

    ANSWER

    The most likely answer is caused by a non-visible character, or characters, being appended at the end of the text you are trying to encode that is causing the slight variation.

    Normally this would be caused by the new line, or line feed character, that you won’t see but is there at the end of the text. It is a valid character that the base64 command will include when it encodes the text you give it.

    It is not wrong, but most times it is not the intention to have the new line character encoded with it.

    Thus, when doing so in command line make sure the new line character is trimmed off. It can be done this way,

    :~$ echo -n "hello world" | base64

    The result would be: aGVsbG8gd29ybGQ=

    Without it, the output is: aGVsbG8gd29ybGQK

    Of course, the case of the character/characters being encoded will also matter.

  • There any free, lightweight app to merge PDF files as one?

    As the name of the title in this post says it all. Okay, maybe not all it says because I want it on Linux desktop.

    Looking for a tool that can combine different PDF into one big PDF file. I don’t need to modify the content of the PDFs. All important is merging them together as a group.

    Sorting it probably comes as second important feature. But I can get on without that as long as it stays in sequence however I added each PDF file.

    Lastly simple. No over the top effects. Prefer GUI app. Open to command line.

    ANSWER

    For that purpose, I have personally used PDF-Shuffler, It is a GUI desktop application on Linux. I used it back then on Ubuntu, but it should be available in all other major distros. Google for it. I know it is included in the official package management repositories of Ubuntu.

    PDF-Shuffler can collate, sort (through drag and drop) and rotate the PDF files individually. As an added bonus, it can crop PDFs too.

    It is a straightforward app. Stable for all those times I’ve used. But my usage is fairly moderate only.

    I also suggest using pdftk for command line if you fancy that kind of stuff. You can combine PDFs into one as simple as:

    :~$ pdftk file-1.pdf file-2.df file-3.pdf output my-merged.pdf

    This tool can do other stuff. You can read its manual for more information. Google about pdftk too for more examples.

  • Support for Ubuntu Unity Desktop after 16.04 LTS

    Can still use the Unity Desktop after Ubuntu 16.04 Xenial Xerus? Is it still supported?

    I like the Unity desktop way of things. Been using it many years now. Read about and tried the new Ubuntu that with Gnome Shell, but I don’t like it much at all. It look clunky with many of missing things from it.

    Come April 2021 Ubuntu 16.04 will EOL. Starting to find alternatives, but if Unity is still out there, I’d pick it over the others.

    ANSWER

    In one word, Yes.

    Still can run on both LTS versions of 18.04 and 20.04. Go ahead and install it with:

    sudo apt install ubuntu-unity-desktop

    Choose Lightdm display manager when asked during install. Best to restart your computer afterwards. Then enjoy.

    Consider that many people have said some weird looks of Unity when installed on said LTS versions appear. I forget, but I think its the window decorations and such. This is supposedly caused by the newer Gnome versions, and unpatched by Ubuntu. Unlike before.

    You may also like to try out an alternative in the Ubuntu Unity Desktop spinoff. Can be found at this website – https://ubuntuunity.org/

    It is not official Ubuntu flavor, but being maintained by some other 3rd party group. The experience is different from just installing 20.04 and then install Unity DE afterwards. Try it out if it suits you.

  • How to convert For loop using Stream in Java

    Creating a Map of Applicant object, where I filter out on the applicant’s age. I only need the first name and last name of the applicant. Using the application ID as the key. The ID is generated integer and unique. Also, testing for null, don’t want that in there. I am using a traditional for loop where I am most comfortable at. But I want to use the Java 8 Stream instead. How is it done?

    My code for this is below:

            Applicant a1 = new Applicant();
            a1.setId(1001);
            a1.setFirstName("Joseph");
            a1.setLastName("Dey");
            a1.setAge(25);
    
            Applicant a2 = new Applicant();
            a2.setId(2001);
            a2.setFirstName("Maxine");
            a2.setLastName("Summers");
            a2.setAge(21);
    
            Applicant a3 = new Applicant();
            a3.setId(3001);
            a3.setFirstName("Jimmy");
            a3.setLastName("Cox");
            a3.setAge(17);
    
            Applicant a4 = null;
    
            List list = new ArrayList();
            list.add(a1);
            list.add(a2);
            list.add(a3);
            list.add(a4);
    
            Map map = new HashMap();
            for (Applicant a : list) {
                if (a != null && a.getAge() > 18) {
                    map.put(a.getId(), a.getFirstName() + " " + a.getLastName());
                }
            }

    ANSWER

    By Statement Lambda in Collectors.toMap – right-hand side is a block. This can become longer to write but sometimes when you have to do more transformations, then it can’t be avoided.

    1       Map map = list.stream()
    2                .filter(applicant -> applicant != null)
    3                .filter(applicant -> applicant.getAge() >= 18)
    4                .collect(Collectors.toMap(applicant -> applicant.getId(), applicant -> {
    5                    return applicant.getFirstName() + " " + applicant.getLastName();
    6                }));

    By Expression Lambda in Collectors.toMap – right-hand side is an expression.

    1       Map map = list.stream()
    2                .filter(applicant -> applicant != null)
    3                .filter(applicant -> applicant.getAge() >= 18)
    4                .collect(Collectors.toMap(applicant -> applicant.getId(), applicant -> applicant.getFirstName() + " " + applicant.getLastName()));

    In both cases above, line #2 the Lambda can be replaced with method reference too. It will look like:

    .filter(Objects::nonNull)

    And on line #4, the same can be done for the Lamba replacing it with a method reference. It will look like:

    .collect(Collectors.toMap(Applicant::getId,  // rest of code ommitted

  • Avro – Unions
    https://www.worldofnubcraft.com/4174/kafka-consumer-error-avro-with-field-type-as-a-union-of-null-and-boolean/

    As a boolean:

    {
    	"fieldOne": "hello world",
    	"fieldTwo": true,
    	"foobar": {
    		"boolean": false
    	}
    }

    If value is null:

    {
    	"fieldOne": "hello world",
    	"fieldTwo": true,
    	"foobar": null
    }

    The above is what a field will look like as output where in Avro that field is defined as one of the Complex Types – Unions. Example below, it declares a schema which may be one of null or boolean.

    {
      "type": [
        "null", 
        "boolean"
      ]
    }
    
  • Convert a Map to POJO in Java

    How do I convert a Map object to my other plain old Java object (POJO) without going into loops and having to write a class using Java reflection, or some other?

    ANSWER

    Well, yes, reflection is one but you didn’t want to do that yourself. For some good reason, I bet. It’s a good exercise if you have all the time in the world. But when faced with deadlines and having to write Unit tests for a whole class you wrote, there must be an easier way.

    There is more than one way, but what I normally use is the Jackson ObjectMapper. Yes, the same one from the com.fasterxml.jackson library.

    Anyway, with ObjectMapper it is pretty straightforward to do so. If I have a Person class like this:

        public class Person {
            private String firstName;
            private String lastName;
        }
    

    My Map object will look like this:

            Map map = new HashMap();
            map.put("firstName", "Johnny");
            map.put("lastName", "Foo");

    Then with ObjectMapper one can simply do this:

            ObjectMapper mapper = new ObjectMapper();
            Person person = mapper.convertValue(map, Person.class);

    Alternatively, the keys in the Map may not align with the fields in the Person class. Well, I usually encounter this when working with JSON objects with lots of crazy looking field names. Something like this – NZT_Mor_First_Name__c – which I clearly don’t want my class field name to be like.

    Well, we can use @JsonProperty annotation which is part of Jackson by the way and assign that our class field. The Person class will now look like:

        public class Person {
    
            @JsonProperty("NZT_Mor_First_Name__c")
            private String firstName;
    
            @JsonProperty("NZT_Mor_Last_Name__c")
            private String lastName;
        }

    Again the Map will hold these values:

            Map map = new HashMap();
            map.put("NZT_Mor_First_Name__c", "Jose");
            map.put("NZT_Mor_Last_Name__c", "Yamut");

    Now it will map out those weird looking key names to its corresponding class fields.

    One thing to note is you might need to set ObjectMapper features such as ignoring unknown properties and make it case insensitive. Allow it a bit more room to wiggle, wiggle.

            ObjectMapper mapper = new ObjectMapper()
                    .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
                    .enable(MapperFeature.ACCEPT_CASE_INSENSITIVE_VALUES);

  • Should I quote Strings in YAML?

    Should I or should I not? Is it required? Will it work even without quotes – single or double?

    ANSWER

    I’ve asked myself these questions several times. Often I end up double-quoting long strings, but not for one word ones or shorter strings. Which makes it rather inconsistent. Especially if that string contains characters like a forward slash, a colon or semi-colon. Like when you have a URL as a value. I suppose it’s out of habit.

    Thing is, it is not required. Strings can be quoted or not. There is no difference. It will still work with or without it. Even with spaces in that string. YAML allows it. Below are 2 examples:

    phrase: 'The quick brown fox jumps over the lazy dog.'
    poem: "Hey, diddle, diddle. The cat and the fiddle. The cow jumped over the moon."

    The key part of the key-value pair can also be quoted too. The YAML won’t error out. Again, it’s allowed. So this is valid:

    'foo':
      "bar": foobar

    Single quote or double quotes don’t matter. It can be mixed. Above examples are both acceptable.

    However, not quoting is not true in all cases. There are certain instances when it is required such as when there is a colon in the key. In this case, the key needs to be quoted.

    'key:': value

    What about quotes in the value itself?

    CORRECT - phrase1: 'The quick ''brown'' fox jumped over the lazy dog.'
    WRONG- phrase2: "The quick ""brown"" fox jumped over the lazy dog."
    CORRECT - phrase3: "The quick \"brown\" fox jumped over the lazy dog."
    WRONG - phrase4: "The quick '"brown"' fox jumped over the lazy dog."
    CORRECT - phrase6: The quick 'brown' fox jumped over the lazy dog.
    CORRECT - phrase7: The quick "brown" fox jumped over the lazy dog.

    Finally, what does YAML mean?

    It is short for – YAML Ain’t Markup Language.

  • What’s my Windows version

    You’ll probably get asked this once or twice. Especially when your Windows computer is not working right, and you are running all over the Internet trying to look for answers. Perhaps would-be good Samaritans might ask this off you as well.

    And you reply, “Windows 10”. But rightfully so.

    After all, isn’t that the Windows that is installed on your machine right now. Well, yes. Then again, no. No not in the sense that you are wrong. But sometimes the answer to the question of what Windows version is installed on your PC might be something else. Sometimes support may ask you this, and likely they will tell you how to give them the answer they are looking for. If you don’t already know this, then this can save time and misunderstanding. Below are the steps on how to get that information.

    What version is my Windows?

    • Go to the Start Menu. Click it. Press the Windows key
    • Type “Run”. The shortcut key is Windows key + R.
    • Type “winver” in the field labeled with Open. You may also type winver in the search box on your taskbar if you have that one.
    • Click OK or press enter
    • Small dialog Windows will pop out title – About Windows.

    The information will be found on this pop up window. On the first few lines you should see something like:

    Microsoft Windows
    Version 2004 (OS Build 19041.630)

    Note: Don’t include quotes when typing in those words in the steps.

  • Is there a Clipboard for Windows 10?

    What are the freely available Clipboard programs, if any, for Windows 10? Are there such? I don’t want ads in it and I prefer it simple as possible. No crazy or complex features. I’m only after a simple copy-paste of the short history of what I’ve copied on my desktop. I find this useful for my productivity. I somehow always ending up in open a Notepad and copying the items in there. It works but a clipboard would be better in my opinion.

    ANSWER

    Windows 10 already comes with a built-in Clipboard Manager. This was from an update some time ago. However it is not enabled by default, buried somewhere in the Settings and you will have to activate it. This feature is not very well known. But it is there and it works as expected.

    To activate:

    Open Settings via any of the following ways:

    • You can either search for it if you have that search bar on your Windows taskbar.
    • Start typing “Settings” when you have the Windows Start Menu opened.
    • Open the Start Menu then, then click on the Gear icon on the left hand side of the menu.
    • Windows + i shortcut key combo.

    Once you are in Settings, go to System. That should be the first icon entry at the top.

    You will be taken to another page where there are items at the left hand side. Scroll down and find Clipboard.

    Under Clipboard history, toggle the button to On.

    To get to your clipboard history, simply press Windows + V shortcut key combo. It will appear as a floating box over your last active application. Otherwise, it will show up on the right side of the desktop on top of the system tray.

    The clipboard can contain a max of 25 entries. It is a FIFO (first in, first out) stack so the oldest entry will go out first once that entry limit is hit.

    It supports plain text, HTML and images up to 4MB size.

    Your clipboard history can be synced across your Windows devices. Be warned that if you enable this it means you are allowing Windows to save the history on Microsoft servers. Make sure you don’t have sensitive information in there when the Sync functionality is enabled.

  • Re-publish Kafka record not setting partition number?

    Well, I plan to re-publish Kafka records that my app is consuming to another Kafka topic on another host (internal only). This sort of lets other groups consume data from this topic without having to create connections outside of the private network, since the original data source is a 3rd party vendor. They can then also do their own transformations or other business logic on it as if they were consuming from the original source. Delay from source to re-publish should be minimal. Will still be close to real time.

    What I normally do when producing records is not to set a partition by default. Would this be okay when re-publishing records? Will there be conflict with original record partition number to the target topic partition?

    ANSWER

    How many partitions does your target topic have? Do you have freedom to create as many partitions as the source?

    (1) If you can create 1:1 partitions then my suggestion is to retain the original partition number of that record when you publish to the destination topic.

    (2) You can also assign the partition in a round-robin way when you have lesser partitions on your target topic. Save metadata info of that record in the headers, such as original partition assignment and etc. Perhaps that will be useful down the line for your consumers.

    (3) Lastly, you can NOT assign a partition number. Instead, let Kafka do the magic for you. When no partitions are set, Kafka will determine the next partition in a round robin method. You can do this with a null value instead of an int for partition number.

    Bottom line is that it depends on the project requirements, I suppose, or more so on the infrastructure of your destination Kafka.

  • Can’t copy text from webpage?

    Sometimes I come upon a website that I cannot copy text from a HTML web page. Simply cannot click and highlight the lines I try to select for copying. I thought that my browser/mouse was not working. But I go to other sites, I am able to highlight/copy normally. They must’ve done something on that page probably to prevent content from being lifted of the page easily?

    Why is this and how do they do it? Is this a javascript in the page that prevents me from copying?

    ANSWER

    Could be a script on the webpage. I’m certain that can be done or already been done through Javascript before.

    I know that the same effect can be achieved via CSS alone. It is easier, cleaner and does not add to another Javascript messing up or slowing down a site. I prefer this method over the other.

    Below are the CSS lines that does what you want. Different ones for different browsers. It is vendor specific for some, but does the same exact thing.

       user-select: none; /* Supported by Chrome, Firefox & Opera */
      -moz-user-select: none; /* Firefox (older) */
      -ms-user-select: none; /* Edge */
      -khtml-user-select: none; /* Konqueror */
      -webkit-touch-callout: none; /* Safari for iOS */
      -webkit-user-select: none; /* Safari for Mac */
    

    Try it out. You can make it for entire page/site.

    * {
         /* CSS lines go here */
    }

    Or you can make it so only targeted content will have it using Class or ID selectors.

    #text-no-select {
         /* ID selector -  CSS lines go here */
    }
    
    .text-no-select {
         /* Class selector -  CSS lines go here */
    }

    Be aware this does not totally prevent anyone from copying content on a website. There are many other ways to go around this or even with a Javascript impementation. It is a minor roadblock.

  • How to make IntelliJ check and create SerialVersionUID

    When the class implements Serializable I want the serialVersionUID field to be auto-created by IntelliJ IDE. This feature comes in automatically in Eclipse. But the former does not.

    How do I make IntelliJ create the field or warn me that it is not defined in the class yet?

    ANSWER

    It is not turned on by default in IntelliJ. Can be easily done by going to the following:

    File > Settings > Editor > Inspections > Java > Serialization Issues

    Then find and select – Serializable class without ‘serialVersionUID’ – by checking on the box to the right of it.

    Similarly, you can search for it once in File > Settings. Keyword for search can be – ‘serialVersionUID’ – without the quotes.

    The path or location of this feature on IntelliJ may vary. It should be the same on Linux and Windows for versions 2019 and 2020.

    This will only throw a warning. It does not magically create the field in all those classes that implements Serializable straight away. But then IntelliJ will help you create it, like any other decent IDE out there. Go to the class name declaration, you may find that it is subtly highlighted in yellow to hint that there is a user action that can be done. Hover then click on the option – Add ‘serialVersionUID’ field – and you will get the desired result like this one:

    private static final long serialVersionUID = 6265605531073886420L;
  • Database tables map One To Many without foreign key in @JoinColumn

    Possible to not have foreign key relationship in child table to its parent in the database, while in JPA it will still be able to map out fine? How will this be done?

    Can I still use @JoinColumn to define the field for reference back to the parent table?

    This is a one-to-many relationship. One parent record, many child records.

    I only care about writes to the database tables right now.

    ANSWER

    Yes, no FKs defined in the database is fine. JPA will still be able to map out there relationships as defined in your entity classes.

    In fact, enabling – spring.jpa.generate-ddl – in your application properties file will create the necessary Foreign Key and/or Unique Key constraints in the database. This is vendor dependent however.

    For a One To Many relationship, it is straightforward to do. Example below definition below:

        @OneToMany(cascade = CascadeType.ALL)
        @JoinColumn(name = "recommendation_id")
        private List commentList;

    This will map out the entity object values to the Comment table, assuming that is the name of the target table. Each one will be persisted to the child table along with the ID of the parent Recomendation under the recommendation_id column.

  • How to ignore unknown fields when parsing JSON using Jackson

    In Java, there is Jackson 2 library that is very popularly used when reading JSON objects and mapping those values out to a POJO.

    Happy path, as long a I have all the fields from the JSON defined in the POJO then okay. In a perfect world it will work 100%.

    But there is no perfect world. The JSON object in other scenarios can contain unknown fields. These are not in my POJO. Application fails from reading that JSON to POJO.

    Getting this error:

    Exception in thread "main" com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "status" (class com.example.dto.Evaluation), not marked as ignorable (6 known properties: "Book",

    ANSWER

    Use this Jackson annotation at a class level. This has to be configured per class. That should do it. Will ignore any unknown properties silently including nested objects.

    @JsonIgnoreProperties(ignoreUnknown = true)

    When you are using Jackson ObjectMapper directly, that can be configured to ignore unknown properties globally as well.

    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

  • How Do I Decode An OpenShift Secret In A Mounted Volume?

    Mounting an OpenShift Secret to its own volume is straightforward. There are plenty of examples on how to do it. The Web is littered with examples. Next, the most common thing any manual, guide or tutorial would say is to encode the secret in Base64.

    For example I have a SSL certificate stored in a Java KeyStore file format or JKS. The recommended way is to store it in a Secret instead of ConfigMap since it is sensitive information. Of course, that goes without saying the JKS file is password-protected.

    Second, it must be as a Base64 string before I save it as OpenShift Secret.

    How do I get the Base64 string to be decoded in the mounted volume? This one does not seem to get many answers.

    Do I need to include shell commands to decode it and write it to a folder?

    Which folder should I write it to as best practice?

    ANSWER

    #1 The encoded JKS Secret as an environment variable

    This is an option but I’m not a fan of it. The JKS file when encoded can become very long, especially when the file size is large. I don’t think environment variables were meant to be used like this – hold very long text values. That said, this is an easier implementation.

    Map out the secret as an env var in OpenShift or Kubernetes. Then you can use that env var to echo the value and write it out to a file.

    echo -n $SECRET_JKS_VAR | base64 --decode > /file/path/to/decoded-secret.jks

    #2 Mount for read, mount for write

    You have the secret mounted to a file path. That is for reading. Now you need to decode, which means writing to a file so your application can read it back unencoded.

    First, define a mount point as and empty directory. It must be writable. Then make it memory only.

    Next, read the JKS file from its mount point, write it out to the empty dir mount point.

    cat /mount/file/path/for-reading/encoded-secret.jks | base 64 --decode > /mount/file/path/for-writing/decoded-secret.jks

    I like this approach better. It makes more sense rather than mapping a very long base64-encoded text value as an environment variable. The caveat is here is slightly more configurations to be made. Also if I’m not mistaken the in-memory volume count against your app memory quota. Should be negligible unless you write thousands of files into it.

    #3 Lastly, write where you can

    Underneath that container is a file system. Where you have permission to write, then do so there. If it’s Linux, then this decision is pretty much arbitrary IMHO. Put it in /tmp or /home or /mnt. Security wise, others might have access to your app’s pod, that means they can get to the Secret as well. But that is another topic.

  • WorPress Editor Won’t Load Content Anymore

    Got this weird WordPress behaviour recently. While most pages load successfully, editing something – like a post or a page – will draw a blank browser tab. Zero content whatsoever. It has the same result for both Firefox and Chrome. Not tried on other browsers.

    ANSWER

    Uncaught EvalError: Refused to evaluate a string as JavaScript because 'unsafe-eval' is not an allowed source of script in the following Content Security Policy directive: "default-src 'unsafe-inline'

    This was the error that I got when I went into the page, opened developer tools, then reloaded the page.

    Caused by additional custom Header policy on the web server of the website. Looks something like this:

    Header set Content-Security-Policy "default-src 'unsafe-inline' 

    Add ‘unsafe-eval’ to go around it. Use of eval() is usually considered bad practice and not secure hence it’s getting blocked until it is allowed by adding it into the policy. Now the Header will look like this after modifying it. Don’t forget to restart the web server.

    Header set Content-Security-Policy "default-src 'unsafe-inline' 

    More detailed explanations can be had here: https://scotthelme.co.uk/content-security-policy-an-introduction/

  • How to Fix Gradle Wrapper Permission Denied Error

    I am getting this “gradlew permission denied” error after pushing my code to my GitLab repository. The build is not able to continue because the gradle wrapper is not able to run.

    What is causing this and how to fix it?

    ANSWER

    From a local terminal/command line, use the Git command that follows to fix this issue:

    git update-index --chmod=+x gradlew
    

    Continue to commit the modifications to the gradlew file.

    Push the changes to your Git repository.

    You can read more at this page: https://www.joseyamut.xyz/2020/08/15/fix-gradlew-permission-denied-on-openshift-deploy/

  • How to show Snap app icon properly on Ubuntu Unity desktop

    Had this issue where after I logged into my Ubuntu desktop all Snap apps icons do not show properly. Instead I see a plain icon in place of what the app icon should be. Have you the same experience?

    This might have been fixed in later Ubuntu LTS releases, I really don’t know. But I am still on 16.04 Xenial Xerus until its EOL. Also, the reason is that I love the Unity Desktop. The Gnome Shell replacement just doesn’t cut it for me.

    I have been looking for a solution on this issue for some time. The 2 main things people point out are:

    – Add /snap/bin to the /etc/environment file, and;

    – Something to do with the profile.

    Neither of those solutions worked for me. But it did work for others according to what I have read so far.

    ANSWER

    To fix this icon issue, create a symlink of the Snap’s .desktop shortcut file to your user’s .local/share/applications directory.

    It is as simple as that. Once done the problem will go away, and you will be left with a nice-looking icon that came with the Snap installation. This won’t go away on following restarts.

    For more details on how to do this fix exactly, refer to this article – https://www.joseyamut.xyz/2020/08/13/getting-that-ubuntu-snap-icon-right-on-unity-shell/

  • How Do I See the List of Users Allowed on a MS SQL Server Database

    I want to know the users that are allowed access to a MS SQL Server database. I only want a specific database. Is there a user list hidden somewhere?

    What are the ways to go about doing this? Is there an app or through a SQL query?

    ANSWER

    Use Microsoft SQL Server Management Studio. That is the fastest way to do it. Find the database from the explorer menu on the left-hand side. Expand the folder icon. Go to the Security folder, then click on Users next. That’s it!

    If you’re using a different SQL client and you can’t see Security > Users from the GUI. Then your other option is through a SQL query.

    This is the query below. More details at this page here: https://www.joseyamut.xyz/2020/08/06/get-user-list-in-a-microsoft-sql-server-database/.

    USE ;
    SELECT name AS username,
           type_desc AS type,
           authentication_type_desc AS auth_type
    FROM sys.database_principals
    ORDER BY type;

    Happy user hunting! =)

  • Kafka Consumer Error – AVRO with Field Type as a Union of null and boolean

    Recently I ran into some issues in consuming Kafka AVRO messages. Everything went well up to the de-serialization of the record from the Kafka topic. It all just went crazy once it was being serialized into JSON. That’s pretty much where the proverbial buck stopped.

    I was scratching my head on why this odd behavior was happening. Looking at the message published on the Kafka topic, it was following the defined AVRO schema as expected. There were no deviations.

    Somehow when being converted to JSON it started throwing an exception. It was always at the same spot every time. It would not go any further.

    Debugging the flow of the program, it showed me that what should have been this:

    {
    	"fieldOne": "hello world",
    	"fieldTwo": true,
    	"foobar": false
    }

    Became something like this:

    {
    	"fieldOne": "hello world",
    	"fieldTwo": true,
    	"foobar": {
    		"boolean": false
    	}
    }

    And that is why the program was throwing an error!

    ANSWER

    The solution I did was to remove null as a field type. Set the field to be strictly boolean. What I wanted was to initially have the state of this field as null. Then further down the line it can be set to either true or false.

    After the AVRO schema was updated, the error went away.

    This was reported to Apache AVRO Jira. More details about this problem here – https://www.joseyamut.xyz/2020/07/29/de-serializing-kafka-messages-with-union-defined-field/

  • Link in Java returns HTTP instead of HTTPS

    Many times your application can be running behind a reverse proxy or a load balancer, and often in between the protocol is just plain old HTTP. This is a very common setup and one that has been around for several years.

    When this happens, when generating URLs through the Java Link class on Spring boot, you might get the wrong scheme or protocol. What should have been HTTPS becomes HTTP. When you’re building APIs that follows HATEOAS/HAL, this becomes an issue. With just a single letter ‘S’ your URLs become invalid.

    First off, this should be already handled properly by the underlying framework but if the proxy in front of your app was misconfigured this leads to the problem happening and it is then difficult, maybe impossible, to tell whether the client connecting to the app used HTTP or HTTPS.

    Luckily, you can force it somehow to use the proper protocol. This is a solution nonetheless, which works, but I would say having the reverse proxy or load balancer configured correctly is the proper way to do it.

    ANSWER

    The band-aid solution is to manipulate your Spring Boot app depending on the environment.

    For example, if I’m just developing/using it locally HTTP is fine. With profiles setup as it ought to be – dev, test, prod – you can get the correct environment and have your URL use HTTP or HTTPS depending on it. When you deploy it to your server, you know you want it to be using secure HTTP so now you can override the Link to use the right scheme in this case.

    Here is a one way on how to do manipulate the protocol or scheme of a Link.

    Oh, and getting the profile can be done in 2 ways that I know of in Spring Boot.

    First is injecting it via annotation.

    @Value("${spring.profiles.active}")
    private String activeProfile;

    and/or autowiring Environment

    @Autowired
    private Environment environment;
     
    public void getActiveProfiles() {
       for (String profileName : environment.getActiveProfiles()) {
          System.out.println("Active profile: " + profileName);
       }  
    }

  • SSH Time out Error

    I am looking for new ideas on how can I do more better.

    Home laptop (home Laptop can access only Linux VM)
    Linux VM (This machine can access only jump box)
    jump box VM

    I can ssh fine from Linux VM to jump box keys are setup.

    one user is set up in Linux VM called joe and Joe .bash_profile looks like this.

    ssh 10.0.0.1 || ssh 10.0.0.2

    Note: There is two nic on jump box if one is down we can use the other nic for login.

    Let’s say first nic is down and when I do telnet from my home laptop (telnet Linux VM) and provide user name joe it should automatically connect us to 10.0.0.1 but one is down it’s giving message timeout and taking a long time to connect to other nic.

    is there any way when I do telnet and give user name check first ssh connection if down automatically connects to other second one like in 2-3 secs?

    Right now it will give us a message

    Time out
    time out
    time out
    And then it will try to connect the second nic.

    I can more clarify if you guys have any more questions for me.

    Go to Source
    Author: John

    ANSWER

    Resolving hosts can add up to the connection attempt, so specifying an IP address directly can shave off some of those precious milliseconds. If it’s only in a local network with the IP addresses all laid out that should not be the case. At least that’s what I think.

    Perhaps explicitly setting the ConnectTimeout option to a shorter one. Like so,

    ssh -o ConnectTimeout=10 user@host

    This can help. Adjust the number to a sweet spot that works for your ssh setup as necessary.

  • How to configure Krusader’s extract context menu to use something other than ark?

    I’ve found this context menu in krusader to be very unreliable over the years, it has hardly ever worked for me. Surely it’s possible to configure the context menu to use a custom command, like simply using the zip , ot tar CLI command. I don’t find this in the application settings.

    The VFS plugins work great, how come this context menu has to use ARK?

    Go to Source
    Author: barrymac

    ANSWER

    Being KDE, it is a very highly configurable desktop environment to the point that it can become overwhelming. It gives you practically a myriad options for customizations for just about everything. I know because I had been a KDE fan/user for several years.

    But I think the issue here is on file associations. Krusader, being a KDE application should follow system-wide settings. I don’t see any reason why it should not. As such, it is in my opinion that the file manager by default will use whatever is associated to handle or open a certain file. I’d look for KDE’s file association settings in the Control Panel or some such. Then assign a different application for that file to your liking. That should do the trick.

    As for more customizations like using your own script perhaps? It could be possible still under file associations to assign a different application. Don’t have a KDE desktop installed right now so I can’t check this out. Certainly can’t remember too, nor have gone to the extent of doing something like this to handle archives.

  • Copying a MySQL 5.6 server settings for a new environment?

    I have a MySQL 5.6 Server running on a Windows 8 VM on a steel case server. It’s been having issues (The Windows 8, which is then causing the MySQL to have issues). Therefore I was tasked with putting the MySQL 5.6 Server on a Windows 10 VM for stability reasons. The amount of ram the server is allowed and other settings have been tweaked over time. Is there an way I can export these settings, so when I install MySQL on my Windows 10 VM, I can just tell it to use the same?

    Go to Source
    Author: bjk116

    ANSWER

    This should be as straightforward as copying the configuration file – my.ini is the default – of the old MySQL server to the new one. It is a regular text file so copying it should not be an issue at all.

    If there are other supporting configuration files for the DB server you might have customized, copy those as well.

    Restart the MySQL server as necessary. If there are issues, like for example when using InnoDB engine, deleting the datadir should fix that quickly. Of course, I’m assuming this is on a fresh MySQL install. Don’t do this otherwise. You can migrate the data properly through a mysqldump for example.

  • No sound playback during call in Slack – Ubuntu 20.04

    I’m on 20.04 and downloaded Slack using snap. I downloaded Spotify via snap as well as my speakers work. Not sure why Slack isn’t working. I tried every single sound source.

    Go to Source
    Author: Dan

    ANSWER

    Is it possible there is another volume control setting for Slack application that was missed out? It is sometimes hidden deep in the Sound Settings under Applications.

    I had a similar experience with Zoom for Linux. I could not hear a sound at all. The main system volume was all the way up. The app was connected to the device’s audio correctly. I reconnected a couple of times. Only to find out later on that there was yet another set of input/output controls for Zoom that was not so obvious. I only had to turn it up to hear sound during a call. By default it always seems to be at 0 when I join a call, which is weird.

  • What firewall should I use?

    What is the most comprehensive free firewall solution available for Windows? Personal machine, not work machine. I see a ton of choices online, but not sure which one to pick.

    Go to Source
    Author: PerpetualLearner

    ANSWER

    For home use I am fine with the built-in and free Windows Firewall (or Windows Defender Firewall) most of the time. It serves its purpose. Does the job. Not overwhelming to use. Customizable enough.

    I would also explore the security options that comes with my home router. Many have it included nowadays, and with a little tweaking, should be able to add an extra layer of protection to one’s home network..

  • Easy way to bypass password on my computer

    I was not able to formule a question so maybe this was already solved, and if that’s the case, sorry.
    But I found a huge vulnerability on my computer. It’s a portable computer with a Win10/Ubuntu 20.04 dual boot.
    When I’m logged in, and that I lock my session, this sends me to the login screen, okay. But then, if I do Ctrl+Alt+F3 to go to the terminal mode, and then do Ctrl+Alt+F7 to leave terminal mode, this simply unlocks my session !
    It doesn’t work at computer start though, the session must be started and locked.
    Note that when I close my computer this doesn’t lock my session even if it’s activated in the settings.
    This is a critical vulnerability but it’s doesn’t work at all on my friend’s computer which is also a Win10/Ubuntu 20 dual boot.
    I don’t know why this happens to me, any idea of solving this ?

    Thanks for you time

    Go to Source
    Author: Double Vé

    ANSWER

    This does not seem to be a normal behavior from what I’ve experienced at all as far as I can remember. I know before I was fond of having my Linux desktop auto-login on startup. I think I also opted to have it login automatically after sleep/suspend. Perhaps the switch to a different TTY/console constitutes as the same behavior. This looks a lot like buggy behavior to me.

    I would go so far as to document on how to replicate it, and report it as a bug. Call the attention of the developers so this can be looked into and fixed if necessary.

  • validationRegex to accept/validate listed characters

    5 to 16 alpha or alphanumeric to include special characters such as:
    ◦*Hyphen ( – )
    ◦*Slash ( / )
    ◦*Backslash ( )
    ◦*Asterisk ( * )
    ◦*Dollar Sign ( $ )
    ◦*Period ( . )
    ◦*Ampersand ( & )
    ◦*Comma ( , )
    ◦*Number Sign ( # )
    ◦*Open Parenthesis ( ( )
    ◦*Closed Parenthesis ( ) )
    ◦*Colon ( : )

    Current code example:

    PASSWORD: {id: password, label: PASSWORD, name: PASSWORD, validationRegex: ^[a-zA-Z0-9]+$, minLength: 5, maxLength: 16, errorMsg: message}

    Go to Source
    Author: Marcus

    ANSWER

    This regular expressions pattern should work to validate that the string is between 5 to 16 characters long, and has alphanumeric only with the special symbols allowed. Escaping those symbols so it is interpreted by regex compiler as a literal.

    ^([a-zA-Z0-9!-\?\\/.\,\$*\&\:()]{5,16})$

    Results for the following samples of strings that pass the pattern and failed.

    Passed

    • thequickbrownfox
    • !hello-world?
    • /hi\/there\
    • two
    • ast*risk*
    • $dollar$sign
    • 192.168.0.1
    • hello,world
    • (xx&:xx)
    • hashtag#allowed
    • 1234567890123456

    Failed

    Falls short of 5 characters or over 16 characters, does not have those special characters in the pattern, and with spaces or other whitespace characters.

    • abc1
    • this%not@allowed
    • iamoversixteencharacterslong
    • spaces not allowed
    • 12345678901234567
  • Need help with .htaccess redirection for WordPress websites

    I am changing the domain of my website.

    But, I am struggling with the domain redirection. I need to implement this wildcard redirection.

    So that I visit.

    https://www.oldomain.com/page1

    It should go to

    https://newdomain.com/page1

    Note: The new domain is without www.

    Can anyone help me how to implement this?

    Go to Source
    Author: Nirmal Kumar

    ANSWER

    A 301 Redirect, or permanent redirect, is recommended when dealing with something similar to this one.

    If you just want to hard redirect anything hitting oldomain.com to newdomain.com then a simple Redirect should do like so:

    	ServerName oldomain.com
            ServerAlias www.oldomain.com
    	Redirect 301 / https://newdomain.com
    

    The above example is also something that you will want to write in a server config like httpd.conf but not in a .htaccess file somewhere on your site directory. It is also clumsy since your old site’s pages – e.g https://www.domain.com/some/page/123 – will redirect only to https://newdomain.com which is the index page of the site.

    So the other option would be Rewrite. It is also in case you don’t have root access to the server, and/or other sites that are not yours are sharing it as well. It would look like the following:

    RewriteEngine on
    RewriteCond %{HTTP_HOST} ^oldomain.com [NC,OR]
    RewriteCond %{HTTP_HOST} ^www.oldomain.com [NC]
    RewriteRule ^(.*)$ http://newdomain.com/$1 [L,R=301,NC]

    The above considers whether the request is written with or without the www subdomain in it. The old links or pages will also get carried over to the new one.

  • How is a source RPM different from unpacking an RPM with rpm2cpio and cpio?

    I am attempting to understand the use of a .srpm aka “source rpm” Red Hat Package Manager package. From what I understand so far, a .srpm is different from a standard .rpm in that it provides the source code and is commonly used during development. I am puzzled on why this is useful because if I run rpm2cpio ./myrpm-1.1-1.x86_64.rpm | cpio -idmv, I can still view the source code. As I understand, even standard RPMs pull down a .tar.gz/bz file which contains the source, and eventually builds this. Could you please clarify how source RPMs are different and why I would want to use one?

    Go to Source
    Author: the_endian

    ANSWER

    As I remember RPM files that end with extensions of .srpm or .src.rpm (I see this more often if I recall correctly) are copies of software source code including the build/compile scripts and instructions. Normally these are archived in tar format, before then being packaged further as RPM.

    Because it is packaged as RPM, source RPMs can very well be installed the same way as any other RPM. The source files will go to a default folder on your Linux.

    So there is the RPM mostly and mainly for binary or compiled software. Then the Source RPM that contains the source code of that software. These were distinctly packaged with the proper file extensions. Rightfully so people don’t get confused. Perhaps some RPM packagers also include the software’s source code in RPM, but I have not seen that yet.

    On a side not, back in the days I used to build RPMs for myself a lot. It became sort of a hobby. This was circa 2006-2009.

    There were a few reasons I did this.

    • Software I want to install on my Linux doesn’t have RPM, only tarballs.
    • I could install software via – .configure + make + make install – terminal kung fu, but it’s easier to track and manage via RPM.
    • Lastly. For fun, and wanted to think I’m cool. (j/k) On a serious note, for learning purposes.

    My memory is a bit foggy on this now. But there was this really cool GUI utility tool that created RPMs for you. I just forgot the name of this little app. You just needed to supply it a copy of the tarball, some other info, then press the button. Magic. This was after I got tired doing it by hand on the Linux terminal, and as soon as I found out about this handy GUI tool, I mostly did it this way.

  • how to get specific character from a log file in linux

    ANSWER

    Assuming that (1) the log file looks as it is AND (2) it is multi-line, then a simple Linux grep command like below should work (even with multiple lines of that line you’re looking for in one log file):

    INPUT | Tested it on dummy logs from sample

    COMMAND | grep -Pn "^Id\s+:\s+(.*)$" *.log

    OUTPUT |

    log101.log:2:Id : UN123P

    log102.log:2:Id : HELLO321

    log103.log:2:Id : STUDE23P

    log104.log:2:Id : Lorem

    log104.log:7:Id : IPsum

    log104.log:12:Id : Dolor

    have a log file , having multiple contents inside the file like and example below is the content of U123.log . I have n number of logs..

    Accepted password for hoover from 10.0.2.2 port 4792 ss
    
    Id : UN123P 
    
    ID_MTCH : UnixProduction
    
    Accepted password for hoover from 10.0.2.2 port 4792 ss
    
    Accepted password for hoover from 10.0.2.2 port 4792 ss
    

    Is there any we can fetch “Id : UN123P” as an output of linux command. We have some 1000’s of logs and from all the logs , trying to fetch the value only starts with ID : and output as “Id : UN123P”

    Pls suggest

    Go to Source
    Author: Arya