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edinplace(1)                  Mail Avenger 0.8.4                  edinplace(1)


NAME

       edinplace - edit a file in place


SYNOPSIS

       edinplace [--error=code] [[--file=file] command [arg ...]]


DESCRIPTION

       edinplace runs command with its input from file (or standard input by
       default), and then replaces the contents of file with the output of
       command.  To the extent possible, edinplace attempts to exit with the
       same status as command.

       If edinplace is run on standard input (no --file option), it must
       inherit a file descriptor 0 that is open for both reading and writing.
       When processing standard input, if edinplace does not encounter a fatal
       error, it rewinds its standard input to offset 0 before exiting.  Thus,
       a script can first run edinplace command, then run another filter
       command such as grep, and the resulting output will be the output of
       grep on command's output.

       If no command is specified, edinplace just rewinds its standard input
       to file offset 0.  In this case, it is an error to supply the --file
       option.  Of course, rewinding only works when standard input is a real
       file (as opposed to a pipe or device).

       There are two options:

       --error=code (-x code)
           Ordinarily, edinplace attempts to exit with the same status as
           command.  However, if edinplace encounters some fatal error (such
           as being unable to execute command), it will exit with status code.
           The default value is 1.  The range of valid exit codes is 1-255,
           inclusive.

       --file=file (-f file)
           Specifies that file should be edited.  Otherwise, edinplace will
           edit its standard input (which must be opened for both reading and
           writing).

       --skipfrom
           Skip the first line of the file if it starts "From ".  If edinplace
           is run without a command, positions the file offset at the start of
           the second line of the file.  If edinplace is run with a command,
           then the first line of the file is neither fed to the command, nor
           overwritten.  This option is useful for running edinplace over mail
           files, which sometimes start with a "From " line specifying the
           envelope sender of the message.  Since "From " is not part of the
           message header, just a Unix convention, some programs are confused
           by the presence of that line.  Note that if you specify a command,
           then edinplace resets the file offset to 0 upon exiting, even if
           the --skipfrom option was present.


EXAMPLES

       The following command prepends the string "ORIGINAL: " to the beginning
       of each line in text file message:

           edinplace -f message sed -e 's/^/ORIGINAL: /'

       The following command runs the spamassassin mail filter program on a
       mail message stored in file message, replacing the contents of message
       with spamassassin's annotated output, and exiting with code 100 if
       spamassassin thinks the message is spam.  If edinplace encounters any
       fatal errors, it will exit with code 111.

           edinplace -x 111 -f message spamassassin -e 100

       (spamassassin reads a mail message on standard input and outputs an
       annotated copy of the message including information about whether or
       not the message is likely to be spam and why.  The -e option to
       spamassassin specifies what exit status spamassassin should use if the
       message appears to be spam; edinplace will use the same exit code as
       the program it has run.)

       To run spamassassin on incoming mail before accepting the mail from the
       remote client, place the following line in an appropriate Mail Avenger
       rcpt file as the last command executed:

           bodytest edinplace -x 111 spamassassin -e 100


SEE ALSO

       avenger(1)

       The Mail Avenger home page: <http://www.mailavenger.org/>.


BUGS

       edinplace does not make a copy of the file being edited, but rather
       overwrites the file as it is being processed.  At any point where
       command has produced more output than it has consumed input from the
       file, edinplace buffers the difference in memory.  Thus, a command that
       outputs large amounts of data before reading the input file can run
       edinplace out of memory.  (A program that outputs data as it reads even
       a very large file should be fine, however.)

       If command crashes or malfunctions for any reason, you will likely lose
       the input file, since edinplace will view this as a program that simply
       outputs the empty file.


AUTHOR

       David Mazieres

Mail Avenger 0.8.4                2013-07-13                      edinplace(1)

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