Change string in file.

changestr.sh

#!/bin/sh

#change string in file
if [[ $# -ne 3 ]]; then
    echo "Wrong number of arguments"
    echo "Usage: $0 FILE FROMSTRING TOSTRING"
    exit 1
fi

SED_FILE=$1
FROMSTRING=$2
TOSTRING=$3
TMPFILE=$SED_FILE.tmp

#escape to and from strings
FROMSTRINGESC=$(echo $FROMSTRING | sed -e 's/\\/\\\\/g' -e 's/\//\\\//g' -e 's/&/\\\&/g')
TOSTRINGESC=$(echo $TOSTRING | sed -e 's/\\/\\\\/g' -e 's/\//\\\//g' -e 's/&/\\\&/g')

sed -e "s/$FROMSTRINGESC/$TOSTRINGESC/g" $SED_FILE  > $TMPFILE && mv $TMPFILE $SED_FILE

if [ ! -f $TMPFILE ]; then    
    exit 0
 else
 	echo "ERROR: Something went wrong."
 	exit 2
fi