#!/bin/bash
#Usage dsed <pattern> <file>

pattern="$1"
file="$2"

#We don't want to have a case like this:
# 's/a'b//
#We need to change that to this:
# 's/a'"'"'b//

pattern=${pattern//\'/\'\"\'\"\'}
if [ "$file" = "" ]; then
    echo "Usage: dsed <pattern> <file>"
    exit;
fi

sedcmd="sed -e '$pattern' $file"
echo $sedcmd

diff <(cat $file) <(eval $sedcmd)

echo -n  "Do you wish to make this change? [yn] "
read answer
if [ "$answer" != "y" ]; then
    echo Aborting;
    exit;
fi

sedcmd=$(echo $sedcmd | sed -e 's/^sed /sed -i /')
eval $sedcmd