NAME

       pamexec - Execute a shell command on each image in a Netpbm image stream

SYNOPSIS

       pamexec

       ["command"]

       [netpbmfile]

       [-check]

       Minimum  unique  abbreviation of option is acceptable.  You may use double hyphens instead
       of single hyphen to denote options.  You may use white space in place of the  equals  sign
       to separate an option name from its value.

DESCRIPTION

       This program is part of Netpbm(1).

       pamexec  reads  a Netpbm image stream as input.  For each image, it runs a specified shell
       command and supplies the image to it as Standard Input (with a pipe).

       netpbmfile is the file name of the input file, or  -  to  indicate  Standard  Input.   The
       default is Standard Input.

       Many  Netpbm programs understand multimage Netpbm streams themselves, so you don't need to
       use pamexec to run the program on the images in the stream.  Ideally, all Netpbm  programs
       would  have that capability, but multi-image streams are a relatively recent invention, so
       older Netpbm programs just process the first image in the stream and then stop.  Even many
       recently  written  Netpbm  programs  work  that way, since the authors aren't aware of the
       multi-image possibility.

       Another way to process a multi-image stream is to use pamsplit to explode it into multiple
       files, one image per file.  You can then process those files.

       To  run  your  command  on a subset of the images in the stream, use pampick to select the
       desired images from the input stream and pipe the result to pamexec.

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ),  pamexec recognizes the following command
       line option:

       -check This causes pamexec to exit without processing any further images  if  the  command
              has a nonzero exit status.

APPLICATIONS

       To make an animated GIF movie:

           pamexec pamtogif myvideo.ppm | gifsicle --multifile >myvideo.gif

LIMITATIONS

       pamexec  assumes all commands consume all of Standard Input.  If yours doesn't (perhaps it
       just exits when it's seen enough),
         you can buffer through a temporary file like this, which copies the
         first 3 lines of every image (the PPM header) to Standard Output:

           pamexec "cat >/tmp/x; head --lines=3 x" myvideo.ppm

HISTORY

       pamexec was new in Netpbm 10.56 (September 2011).

       Michael Pot wrote it, borrowing from pamsplit.

SEE ALSO

       pamfile(1), pampick(1), pamsplit(1), pnm(1), pam(1), cat man page

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master
       documentation is at

              http://netpbm.sourceforge.net/doc/pamexec.html