Recursively update symlinks

update-symlinks.sh

#!/bin/bash

#For updated versions see https://gist.github.com/pcworld
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if [ $# -ne 3 ] # http://www.linuxweblog.com/bash-argument-numbers-check
then
	echo "Recursively updates the target directories of matching symlinks in a given directory with new ones."
	echo "Usage: `basename $0` <directory to search for symlinks in> <path of the symlink target to be replaced> <replace with this>"
	echo
	echo "Example: `basename $0` /home/myuser /opt/formerfolder /var/test/newfolder"
	echo "This will search for symlinks in /home/myuser whose target contains \"/opt/formerfolder\" and will replace \"/opt/formerfolder/\" with \"/var/test/newfolder/\" in their targets."
	echo "Note: If the symlink targets are relative (and not absolute), you might have to consider that for the second parameter."
	
	exit 1
fi

#http://stackoverflow.com/a/1848456
SEARCHFOR=${2%/}
REPLACEBY=${3%/}

#http://superuser.com/a/157832
find $1 -type l \
  -lname "$SEARCHFOR/*" \
  -printf 'ln -nsf $(readlink %p | sed s,'"$SEARCHFOR"'/,'"$REPLACEBY"'/,) $(echo %p | sed s,'"$SEARCHFOR"'/,'"$REPLACEBY"'/,)\n' \
| bash

#readlink: use "-v" to display error messages (e.g. if file doesn't exist)