Tech@Sakana – A sysadmin’s blog

One of the features of bash I’ve too long overlooked is its history expansion. In this post I’ll show a few examples to get a grip at it.
(more…)

If you need to identify broken symlinks, you can do the following :
find -L . -type l

The -L options instructs find to follow symlinks when possible. Hence no “working symlink” will ever get returned as the targets won’t match -type l (meaning “file is a symlink”).

On the other hand, find will not be able to follow broken symlinks, so the information will be taken from the symlink itself and not from the non-existent or otherwise unreachable target. The -type l will then be a match and the broken symlink filename will be returned.

Case solved

Thanks to the “Ferg’s Gaff” blog (especially the comments) for showing the way !

I ran into this into the following article, “Learn 10 good UNIX usage habits“. This article is mainly common sense, but there are interesting points, such as :

• avoid piping when you can, in order to save performance (the classical construct grep | wc to count the lines is useless as most versions of grep can count with grep -c)
• use awk to “grep” on a specific field of a line with “… | awk ‘$1 == “XXX”‘ which is cool and I never use
• the find | xargs construct (I’d add “find -print0 | xargs -0″, useful if your find brings back filenames with a space inside …)

All in all it is worth a reading, if only to refresh your memory.