This program is part of Netpbm.

All Netpbm formats that have samples in pure binary format with multi-
ple bytes are defined to have them in big endian (most significant
byte first) order. However, there exist variations on these formats,
primarily developed before official multibyte Netpbm formats existed,
that are identical to Netpbm formats in every respect except that sam-
ples are in little endian (least signficant byte first) order.

pamendian reverses the byte order of the sample to convert between the
two formats. If the input is true PAM, PGM, or PPM, the output is the
little endian variation on that format, and vice versa.

Programs that come with the Independent Jpeg Group's JPEG library are
known to use the little endian variation of PGM and PPM.

The reason some programs use this variant is that at one time during
Netpbm's darkage,there was a version of Netpbm around that used it.
But it was never formally specified.

This program takes input only on Standard Input. Its output is always
on Standard Output.

You should never have to use this program with images generated by
programs in the Netpbm package or programs that use the Netpbm
libraries. If you do, that probably means something needs to be fixed
in those programs. The Netpbm converter for any graphics format that
represents numbers in little endian form should properly reverse the
bytes to create correct Netpbm output.

If you create a Netpbm image from a generic stream of samples, using
rawtopgm or rawtoppm, use options on those programs to declare the
endianness of your input, thus creating correct endianness in your PGM
or PPM output.

pamdepth, rawtopgm, rawtoppm, pnm

netpbm documentation 16 March 2002 Pamendian User Manual(0)