Pamexec User Manual(1) General Commands Manual Pamexec User Manual(1)
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 dou-
ble 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 In-
put (with a pipe).
netpbmfile is the file name of the input file, or - to indicate Stan-
dard 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 au-
thors aren't aware of the multi-image possibility.
Another way to process a multi-image stream is to use pamsplit to ex-
plode 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 im-
ages 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
netpbm documentation 21 December 2021 Pamexec User Manual(1)
Generated by dwww version 1.15 on Sat Jun 29 02:11:38 CEST 2024.