Real life diff use:
I want to copy only the missing 'jpg' files at the ~/tmp/wallpapers
diff -u ~/img/backgrounds ~/tmp/wallpapers
Only in /home/sergio/tmp/wallpapers: .git
Only in /home/sergio/tmp/wallpapers: .gitignore
Only in /home/sergio/tmp/wallpapers: README.md
Only in /home/sergio/tmp/wallpapers: thumbs
Only in /home/sergio/img/backgrounds: wallpaper-1791868.jpg
Only in /home/sergio/img/backgrounds: wallpaper-2099153.jpg
Only in em /home/sergio/img/backgrounds: wallpaper-2226037.jpg
Using awk with two field separators [: ] I only need the third and fifth fields to compose a copy command:
diff -u ~/img/backgrounds ~/tmp/wallpapers | awk -F'[: ]' '/backgrounds/ {print $3"/"$5}'
/home/sergio/img/backgrounds/wallpaper-1791868.jpg
/home/sergio/img/backgrounds/wallpaper-2099153.jpg
/home/sergio/img/backgrounds/wallpaper-2226037.jpg
Now I only have to add some strings to my awk command and pipe the result to the shell
"cp " ............... copy comand with space
$3 ................ the third fild - the basename
"/" ................ add the slash so we do not mess things up
$5 ................. the missing file name
" ~/tmp/wallpapers" destination folder
| sh ................ pipe the preceding command to the shell
diff -u ~/img/backgrounds ~/tmp/wallpapers \
| awk -F'[: ]' '/backgrounds/ {print "cp " $3"/"$5" ~/tmp/wallpapers/"}' | sh
An interesting thing is that the backgrounds folder has no .git files on it but the wallpapers do, that's why I am filtering '/backgrounds/' with awk and not using recursion '-r', because the wallpapers folder has a thumbs subfolder
Top comments (0)