fotanus fotanus - 1 month ago 13
Bash Question

Delete all broken symbolic links with a line?

For a given folder, how can I delete all broken links within it?

I found this answer that shows how to delete one broken link, but I can't put that together in only one line. Is there a one-liner for this?

A broken symbolic is a link that points to a file/folder that doesn't exists any longer.

Answer

Here's a POSIX way of deleting all broken symbolic links in the current directory, without recursion. It works by telling find to traverse symbolic links (-L), but stopping (-prune) at every directory-or-symbolic-link-to-such.

find -L . -name . -o -type d -prune -o -type l -exec rm {} +

You can also use a shell loop. The test -L matches symbolic links, and -e matches existing files (excluding broken symlinks).

for x in * .[!.]* ..?*; do if [ -L "$x" ] && ! [ -e "$x" ]; then rm -- "$x"; fi; done

If you want to recurse into subdirectories, this technique doesn't work. With GNU find (as found on non-embedded Linux and Cygwin), you can use the -xtype predicate to detect broken symbolic links (-xtype uses the type of the target for symbolic links, and reports l for broken links).

find -xtype l -delete

POSIXly, you need to combine two tools. You can use find -type l -exec … to invoke a command on each symbolic link, and [ -e "$x" ] to test whether that link is non-broken.

find . -type l -exec sh -c 'for x; do [ -e "$x" ] || rm "$x"; done' _ {} +

The simplest solution is to use zsh. To delete all broken symbolic links in the current directory:

rm -- *(-@D)

The characters in parentheses are glob qualifiers: - to dereference symlinks, @ to match only symlinks (the combination -@ means broken symlinks only), and D to match dot files. To recurse into subdirectories, make that rm -- **/*(-@D).