#!/bin/sh
# poor replacements for standard unix tools when all that's available is
# ash or bash shell
# most won't work with binary files at all, and destroy formatting of text

die () {
 echo "$@" >&2
 exit 1
}

cat () {
 if [ "$1" ]; then
  for file in $@; do
   exec 3<$file
   while read -u 3 whatever; do
    echo $whatever
   done
   exec 3<&-
  done
 else
  while read whatever; do
   echo $whatever
  done
 fi
}

grep () {
 if [ -z "$1" ]; then
  die "Usage: grep PATTERN [[FILE] ...]"