Do typical system call interfaces allow reducing the size of a file (without replacing it with a different...












0















Is there a way to open() a file and cause it to shrink? One can, of course, open them in append-mode or seek to the end and write to cause them to grow. However, as far as I know, there is no method to shrink a file via typical unix-style system call interfaces.



The only way to do so, as far as I know, is by faking it by creating a new shorter file and rename() it in place of the older one.



I just wanted confirmation, because I saw an answer that implied that it was possible to make file editors that worked directly on a file instead of going through the process of making a new one and renaming it in place.



I've always thought that the file api in libc and unix-style system call interfaces did not allow for the shrinking of files to ease implementation of filesystems and maybe avoid usage patterns that might contribute to fragmentation.









share



























    0















    Is there a way to open() a file and cause it to shrink? One can, of course, open them in append-mode or seek to the end and write to cause them to grow. However, as far as I know, there is no method to shrink a file via typical unix-style system call interfaces.



    The only way to do so, as far as I know, is by faking it by creating a new shorter file and rename() it in place of the older one.



    I just wanted confirmation, because I saw an answer that implied that it was possible to make file editors that worked directly on a file instead of going through the process of making a new one and renaming it in place.



    I've always thought that the file api in libc and unix-style system call interfaces did not allow for the shrinking of files to ease implementation of filesystems and maybe avoid usage patterns that might contribute to fragmentation.









    share

























      0












      0








      0








      Is there a way to open() a file and cause it to shrink? One can, of course, open them in append-mode or seek to the end and write to cause them to grow. However, as far as I know, there is no method to shrink a file via typical unix-style system call interfaces.



      The only way to do so, as far as I know, is by faking it by creating a new shorter file and rename() it in place of the older one.



      I just wanted confirmation, because I saw an answer that implied that it was possible to make file editors that worked directly on a file instead of going through the process of making a new one and renaming it in place.



      I've always thought that the file api in libc and unix-style system call interfaces did not allow for the shrinking of files to ease implementation of filesystems and maybe avoid usage patterns that might contribute to fragmentation.









      share














      Is there a way to open() a file and cause it to shrink? One can, of course, open them in append-mode or seek to the end and write to cause them to grow. However, as far as I know, there is no method to shrink a file via typical unix-style system call interfaces.



      The only way to do so, as far as I know, is by faking it by creating a new shorter file and rename() it in place of the older one.



      I just wanted confirmation, because I saw an answer that implied that it was possible to make file editors that worked directly on a file instead of going through the process of making a new one and renaming it in place.



      I've always thought that the file api in libc and unix-style system call interfaces did not allow for the shrinking of files to ease implementation of filesystems and maybe avoid usage patterns that might contribute to fragmentation.







      files filesystems





      share












      share










      share



      share










      asked 5 mins ago









      JoLJoL

      1,089311




      1,089311






















          0






          active

          oldest

          votes











          Your Answer








          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "106"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: false,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: null,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f496104%2fdo-typical-system-call-interfaces-allow-reducing-the-size-of-a-file-without-rep%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          0






          active

          oldest

          votes








          0






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Unix & Linux Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f496104%2fdo-typical-system-call-interfaces-allow-reducing-the-size-of-a-file-without-rep%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          Histoire des bourses de valeurs

          Why is there Russian traffic in my log files?

          Rename multiple files to decrement number in file name?