This program is part of Netpbm.
pamfile reads one or more Netpbm files as input and writes out short descriptions of the image type, size, etc. This is partly for use in shell scripts, so the format is not particularly pretty.
By default, pamfile reads only the header of the input file. If that file is a pipe, that might cause problems for the process that is feeding the pipe. In that case, see the -allimages option.
This option also causes pamfile to read all the images from the input stream, whereas without it, pamfile reads only the header of the first one. If the input stream is from a pipe, the process that is feeding the pipe might require the entire stream to be consumed. In that case, use this option even if the stream contains only one image.
This option has no effect if you also specify -count.
Note that before July 2000, a file could not contain more than one image and many programs ignore all but the first.
This option was new in Netpbm 9.5 (July 2000).
As with -allimages, this causes pamfile to read all the images.
This option was new with Netpbm 10.31 (December 2005).