• Björn Tantau@swg-empire.de
        1001·
        8 个月前

        Yeah. It could just as well have issued a file not found error when you try to touch a nonexistent file. And we would be none the wiser about what we’re missing in the world.

        • 4am@lemm.ee
          213·
          8 个月前

          “Do one thing and do it very well” is the UNIX philosophy after all; if you’re 99% likely to just create that missing file after you get a file not found error, why should touch waste your time?

          • stebo@lemmy.dbzer0.com
            20·
            8 个月前

            with this logic, any command that moves, copies or opens a file should just create a new file if it doesn’t exist

            and now you’re just creating new files without realising just because of a typo

          • Kusimulkku@lemm.ee
            9·
            8 个月前

            But this directly goes against that philosophy, since now instead of changing timestamps it’s also creating files

            • kautau@lemmy.world
              10·
              8 个月前

              You can pass -c to not create a file, but it does go against the philosophy that it creates them by default instead of that being an option

              EDIT: Looking closer into the code, it would appear to maybe be an efficiency thing based on underlying system calls

              Without that check, touch just opens a file for writing, with no other filesystem check, and closes it

              With that check, touch first checks if the file exists, and then if so opens the file for writing

    • Züri@lemmy.ml
      33·
      8 个月前

      We use it to trigger service restarts.

      touch tmp/service-restart.txt

      Using monit to detect the timestamp change and do the actual restart command.

    • magic_lobster_party@kbin.run
      211·
      8 个月前

      I sometimes use cat to concatenate files. For example, add a header to a csv file without manually copy and paste it. It’s rare, but at least more frequent than using touch.

    • marcos@lemmy.world
      14·
      8 个月前

      When you updated a Django server, you were supposed to touch the settings.py file so the server would know to reload your code. (I haven’t used any for a long time, so I don’t know if it’s still the procedure.)

      There are many small things that use it.

    • NotSteve_@lemmy.ca
      13·
      8 个月前

      I used it recently to update the creation date of a bunch of notes. Just wanted them to display in the correct order in Obsidian. Besides that though, always just used it for file creation lol

    • noproblemmy@programming.dev
      13·
      8 个月前

      cat

      Ahhhhh, fuck. I’m quite noob with linux. I got into some rabbit hole trying to read the docs. I found 2 man pages, one is cat(1) and the other cat(1p). Apparently the 1p is for POSIX.

      If someone could help me understand… As far as I could understand I would normally be concerned with (1), but what would I need to be doing to be affected by (1p)?

      • survivalmachine@beehaw.org
        7·
        8 个月前

        The POSIX standard is more portable. If you are writing scripts for your system, you can use the full features in the main man pages. If you are writing code that you want to run on other Linux systems, maybe with reduced feature sets like a tiny embedded computer or alternates to gnu tools like alpine linux, or even other unixes like the BSDs, you will have a better time if you limit yourself to POSIX-compatible features and options – any POSIX-compatible Unix-like implementation should be able to run POSIX-compliant code.

        This is also why many shell scripts will call #!/bin/sh instead of #!/bin/bash – sh is more likely to be available on tinier systems than bash.

        If you are just writing scripts and commands for your own purposes, or you know they will only be used on full-feature distributions, it’s often simpler and more comfortable to use all of the advanced features available on your system.

      • Phoenix3875@lemmy.world
        2·
        8 个月前

        If you execute a binary without specifying the path to it, it will be searched from the $PATH environment variable, which is a list of places to look for the binary. From left to right, the first found one is returned.

        You can use which cat to see what it resolves to and whereis cat to get all possible results.

        If you intentionally wants to use a different binary with the same name, you can either directly use its path, or prepend its path to $PATH.

    • Crow@lemmy.blahaj.zone
      71·
      8 个月前

      I mean, timestamps aren’t really all that useful. Really just if you do some stuff with makefiles but even then it’s a stretch. I did once use cat for its intended purpose tho, for a report. We split up the individual chapters into their own files so we have an easier time with git stuff, made a script that had an array with the files in the order we wanted, gave it to cat and piped that into pandoc

    • Trainguyrom@reddthat.comEnglish
      93·
      8 个月前

      Touch is super useful for commands that interact with a file but don’t create the file by default. For example, yesterday I needed to copy a file to a remote machine accessible over ssh so I used scp (often known as “secure copy”) but needed to touch the file in order to create it before scp would copy into it

    • ik5pvx@lemmy.world
      2·
      8 个月前

      Yes, when you are for example checking if the permissions in the directory are correct, or if you want to check if your nfs export is working. It’s one of those commands that once you know it exists, you WILL find a way to use it.

  • null@slrpnk.net
    411·
    8 个月前

    Is there a command that’s actually just for creating a new file?

    • Gamma@programming.devEnglish
      36·
      8 个月前

      Nope. If you open a nonexistent path and you have permissions to write to that directory, then that file is created.

      • 48954246@lemmy.worldEnglish
        21·
        8 个月前

        Feels dangerous to run. What happens if the file already exists and has something important in it?

        touch -a is probably better

        • gaterush@lemmy.world
          9·
          8 个月前

          The other command could just be printf '' >> file to not overwrite it. Or even simpler >>file and then interrupt

    • Midnitte@beehaw.orgEnglish
      8·
      8 个月前

      I mean, nano filename will work, but there’s no mkfile that I can find…

      $>filename would also work, but it’s not explicitly for creating a new file

    • tranzystorek_io@beehaw.orgEnglish
      6·
      8 个月前

      most shells will accept outputting from a silent command to a file, e.g. :> foo.txt (where : is the posix synonym to the true command)

    • dan@upvote.au
      4·
      8 个月前

      How often do you actually need a blank file though? Usually you’d be writing something in the file.

      • null@slrpnk.net
        1·
        8 个月前

        I’m betting that’s why none ever materialized. Most tools that can manipulate a file, can also create that file first, so there’s just never been a usecase.

        Right-clicking the desktop to create a new txt file in Windows feels so natural, but I can’t really think of any time you’d want to create a new file and do nothing with it in a CLI.

          • null@slrpnk.net
            1·
            8 个月前

            But even still, what’s a realistic usecase that would that involve needing a blank, unmodified file in that instance?

            • indepndnt@lemmy.world
              6·
              8 个月前

              One use case is if you’re running a web server that is configured to return a “maintenance” page instead of the live site if a particular file exists. Which is actually pretty cool because then you don’t have to update the config when you need to do something or let your users get a bunch of 502 errors, you just touch maintenance and you’re good.

  • RustyNova@lemmy.world
    291·
    8 个月前

    I’m way to used to doing nano file.txt that I always forget about touch.

    Although most times, if I create a file, it’s to put something in it