Constant file size

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  • Adrián E. Córdoba
    #1

    Constant file size

    Hi, there!
    I'm developing a little application which must record some events in a
    log file (.txt).
    How can I delete the first line in the log file every time I add a new
    line at the end, in order to keep constant the file size?

    Thank you in advance.
    --
    Adrián E. Córdoba

    Tags: None
    • Andy
      #2
      Re: Constant file size

      If you need logging, I suggest looking at the log4net project, found at
      the Apache Foundations site. They have a LogFileAppender , which has
      the functionality you describe.

      HTH
      Andy


      Adrián E. Córdoba wrote:
      Hi, there!
      I'm developing a little application which must record some events in a
      log file (.txt).
      How can I delete the first line in the log file every time I add a new
      line at the end, in order to keep constant the file size?

      Thank you in advance.
      --
      Adrián E. Córdoba

        Comment

        • Adrián E. Córdoba
          #3
          Re: Constant file size

          Sorry, Andy. But I think LogFileAppender always add new lines to the
          log file, so the file increase its size.
          I need to keep constant the size of the log file.

          Thank you, for your comments.
          --
          Adrián

          Andy ha escrito:
          If you need logging, I suggest looking at the log4net project, found at
          the Apache Foundations site. They have a LogFileAppender , which has
          the functionality you describe.
          >
          HTH
          Andy
          >
          >
          Adrián E. Córdoba wrote:
          Hi, there!
          I'm developing a little application which must record some events in a
          log file (.txt).
          How can I delete the first line in the log file every time I add a new
          line at the end, in order to keep constant the file size?

          Thank you in advance.
          --
          Adrián E. Córdoba

            Comment

            • Jon Skeet [C# MVP]
              #4
              Re: Constant file size

              Adrián E. Córdoba <software.asia@ gmail.comwrote:
              I'm developing a little application which must record some events in a
              log file (.txt).
              How can I delete the first line in the log file every time I add a new
              line at the end, in order to keep constant the file size?
              Two things:

              1) Keeping the same number of lines *won't* keep the file the same
              size, unless all lines are the same size

              2) Deleting the first line in a file involves rewriting the whole file.
              If you use a fixed-size encoding (eg Encoding.Unicod e) and keep the
              lines the same size, you can make it a rolling log file, writing into
              the middle of the file, overwriting lines on a rolling basis.

              --
              Jon Skeet - <skeet@pobox.co m>
              http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
              If replying to the group, please do not mail me too

                Comment

                • Adrián E. Córdoba
                  #5
                  Re: Constant file size

                  Thank you for your comments, Jon.

                  1) It is not necessary the file size will be exactly XX MB. It's enough
                  to keep constant the number of lines.

                  2) Working with a "rolling log file" and writting in the middle of the
                  file, make the file hard to read if you open the file with simple text
                  applications like Notepad because you need to find the oldest line in
                  the file. It is possible but it isn't desirable.

                  Thank you, again.

                  --
                  Adrián


                  Jon ha escrito:
                  Adrián E. Córdoba <software.asia@ gmail.comwrote:
                  I'm developing a little application which must record some events in a
                  log file (.txt).
                  How can I delete the first line in the log file every time I add a new
                  line at the end, in order to keep constant the file size?
                  >
                  Two things:
                  >
                  1) Keeping the same number of lines *won't* keep the file the same
                  size, unless all lines are the same size
                  >
                  2) Deleting the first line in a file involves rewriting the whole file.
                  If you use a fixed-size encoding (eg Encoding.Unicod e) and keep the
                  lines the same size, you can make it a rolling log file, writing into
                  the middle of the file, overwriting lines on a rolling basis.
                  >
                  --
                  Jon Skeet - <skeet@pobox.co m>
                  http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
                  If replying to the group, please do not mail me too

                    Comment

                    • Jon Skeet [C# MVP]
                      #6
                      Re: Constant file size

                      Adrián E. Córdoba wrote:
                      Thank you for your comments, Jon.
                      >
                      1) It is not necessary the file size will be exactly XX MB. It's enough
                      to keep constant the number of lines.
                      Okay.
                      2) Working with a "rolling log file" and writting in the middle of the
                      file, make the file hard to read if you open the file with simple text
                      applications like Notepad because you need to find the oldest line in
                      the file. It is possible but it isn't desirable.
                      In that case, unless you *really* want to rewrite the whole log file
                      each time, I suggest you roll over to different log files (deleting old
                      ones) rather than try to keep it all in one log.

                      Jon

                        Comment

                        • Andy
                          #7
                          Re: Constant file size

                          Just to add to what Jon said, if you do go the rolling log method,
                          log4net does support that natively. No need to write your own.

                          Andy

                          Jon Skeet [C# MVP] wrote:
                          Adrián E. Córdoba wrote:
                          Thank you for your comments, Jon.

                          1) It is not necessary the file size will be exactly XX MB. It's enough
                          to keep constant the number of lines.
                          >
                          Okay.
                          >
                          2) Working with a "rolling log file" and writting in the middle of the
                          file, make the file hard to read if you open the file with simple text
                          applications like Notepad because you need to find the oldest line in
                          the file. It is possible but it isn't desirable.
                          >
                          In that case, unless you *really* want to rewrite the whole log file
                          each time, I suggest you roll over to different log files (deleting old
                          ones) rather than try to keep it all in one log.

                          Jon

                            Comment

                            • Adrián E. Córdoba
                              #8
                              Re: Constant file size

                              Thanks to all.

                              --
                              Adrián

                              Andy ha escrito:
                              Just to add to what Jon said, if you do go the rolling log method,
                              log4net does support that natively. No need to write your own.
                              >
                              Andy
                              >
                              Jon Skeet [C# MVP] wrote:
                              Adrián E. Córdoba wrote:
                              Thank you for your comments, Jon.
                              >
                              1) It is not necessary the file size will be exactly XX MB. It's enough
                              to keep constant the number of lines.
                              Okay.
                              2) Working with a "rolling log file" and writting in the middle of the
                              file, make the file hard to read if you open the file with simple text
                              applications like Notepad because you need to find the oldest line in
                              the file. It is possible but it isn't desirable.
                              In that case, unless you *really* want to rewrite the whole log file
                              each time, I suggest you roll over to different log files (deleting old
                              ones) rather than try to keep it all in one log.

                              Jon

                                Comment

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