Quick and easy script created to be able to get the MD5 digest of a file on either Linux or SunOS

checksum.sh

#!/bin/bash

sysname=`uname -s`

if [ "$sysname" = "SunOS" ]; then
  r=`which md5sum | grep '/md5sum'`
  if [ $r ]; then HAS_MD5SUM="1"; else HAS_MD5SUM="0"; fi

  r=`which digest | grep '/digest'`
  if [ $r ]; then HAS_DIGEST="1"; else HAS_DIGEST="0"; fi
else
  r=`which md5sum &>/dev/null`; if [ "$?" = "0" ]; then HAS_MD5SUM="1"; else HAS_MD5SUM="0"; fi
  r=`which digest &>/dev/null`; if [ "$?" = "0" ]; then HAS_DIGEST="1"; else HAS_DIGEST="0"; fi
fi

if [ "$HAS_MD5SUM" = "1" ]; then
  md5sum $1 | cut -d ' ' -f1
elif [ "$HAS_DIGEST" = "1" ]; then
  digest -a md5 $1
else
  echo "Unable to generate file signature as no digest command could be found"
  exit 1
fi

If your wondering why the different code paths between Linux and SunOS was mainly due to the fact that under SunOS, the pipe out to /dev/null did not work. Hence the usage of grep under SunOS.