Shell Programming and Scripting

# place the script in the dir where filenames need to be added to the .txt file
# use mv to change to original filename if needed: mv $filename.new $filename

for filename in $(ls *.txt)
do
	sed "1s/^/${filename} \n/" ${filename} > $filename.new 
	echo Done ${filename} 
done

 
# place the script in the dir where filenames need to be added to the .txt file
# You can remove the comments if that's what you want...
for filename in $(ls -1 *.txt)
do
        pwd=${PWD}/${filename}
        awk 'BEGIN{print "'$pwd'"}1' $filename > $filename.new
        #rm -f $filename
        #mv $filename.new $filename
done

perl -i -pe 'BEGIN{undef $/;} s/^/$ARGV\n/' `find . -name '*.txt'`