massRename

#!/bin/bash

# By Isaac Good
# Reads filenames from the arguements (eg *)
# Prints them to a file in pairs
# A FROM line and a TO line
# Then it reads the lines back and does a mv FROM TO

tmp=$(mktemp)

quit () {
	rm "$tmp"
	exit $1
}

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

for arg; do
	echo "FROM $arg"
	echo "TO   $arg"
	echo
done > "$tmp"

EDITOR="${EDITOR:-/usr/bin/vim}"
$EDITOR "$tmp"

if [[ ! -f $tmp ]] ; then
	die "Tmp file gone!"
fi

# FROM here
FROM=""
# TO here
TO=""
# Expecting a from or to?
EXPECT="FROM"

# Only parse FROM and TO lines
egrep -e '^FROM' -e '^TO' "$tmp" | while read i; do
	# If we are expecting a FROM, check the line says FROM and the file exists
	if [[ $EXPECT = "FROM" ]] ; then
		if [[ $i = "FROM "* ]]; then
			FROM="${i#FROM }"
			if [[ -f $FROM ]] ; then
				# We now expect a TO to match this FROM file
				EXPECT="TO"
			else
				warn "File does not exist! [$i]"
			fi
		else
			warn "Expected a FROM and got a TO! [$i]"
		fi
	# If expecting a TO...
	else
		if [[ $i = "TO   "* ]]; then
			TO="${i#TO   }"
			if [[ ! -f $TO ]] ; then
				mv -v "$FROM" "$TO"
			else
				# Don't overwrite!
				warn "TO file exists already! [$i]"
			fi
		else
			warn "Expected a TO and got a FROM! [$i]"
		fi
		# Expect a FROM now
		EXPECT="FROM"
	fi
done

quit 0