FSED : flexible sed (looks like the fgrep)

fsed

#! /bin/sh

######################################################################
#
# FSED : flexible sed (looks like the fgrep)
#
# Written by Rich Mikan (richmikan[at]richlab.org) at 2014/04/08
#
# Usage  : fsed <pattern_str> <substitute_str> <file>
#
# * fsed is more flexible substituter than the sed command. This
#   ignores all of the functions which every meta-character of regular
#   expression has, so that you can very easily substitute strings
#   include various meta-characters, e.g. ^, $, \, /, &, and so on.
#
######################################################################

# print the usage and exit
print_usage_and_exit () {
  cat <<__USAGE 1>&2
Usage   : ${0##*/} <pattern_str> <substitute_str>
Version : Tue Apr 08 01:38:30 JST 2014
__USAGE
  exit 1
}

# parse the arguments
if   [ \( $# -le 1 \) -o  \( $# -ge 4 \) ]; then
  print_usage_and_exit
elif [ $# -eq 3 ]; then
  if [ \( -f "$3" \) -o \( -c "$3" \) -o \( -p "$3" \) -o \( "_$3" = '_-' \) ]; then
    file=$3
  else
    echo '*** No such file found' 1>&2
    print_usage_and_exit
  fi
else
  file='-'
fi
pat=$(printf '%s' "$1"            |
      sed 's/\([].\*/[]\)/\\\1/g' |
      sed 's/^\^/\\^/'            |
      sed 's/\$$/\\$/'            )
sub=$(printf '%s' "$2"         |
      sed 's/\([\&/]\)/\\\1/g' )

# transformation
if [ "_$file" = '_-' ]; then
  sed "s/$pat/$sub/g"
else
  sed "s/$pat/$sub/g" "$file"
fi

2013/10/15:
(1)made the code simpler at the sed command lines
(2)made the code acceptable to named pipe files

2013/10/16:
Fix a bug about the file existence check

2013/12/24:
Fix a bug on FreeBSD