faster way to get all files with links in a directory

a4z · 11-04-2014, 11:50 AM

hi,

I search all files that have a link into a directory

currently I go through all files in this directory,
check if this file is a link, and if ...
if this is a huge dir (lots of files), this takes very long time.

I wounder if there is a faster/more efficient way to this

suicidaleggroll · 11-04-2014, 11:54 AM

What do you mean "have a link"? Are you trying to find all links in a directory, or all files that have a link pointing to them from elsewhere? Symbolic links or hard links?

a4z · 11-04-2014, 02:19 PM

symbolic links
I need the targets of all links in a directory

currently I go through all files in the directory, if the file is a link than I readlink the link and the result goes into a list.
and this is, if there are very many files and some of them are symbolic links, a very expensive operation,
so I wounder if there is a better way, maybe a file system that knows something or something else, a magic trick possible :-)

suicidaleggroll · 11-04-2014, 02:40 PM

You can use the -type l flag in find to find symbolic links, then exec to pass it to readlink. It would probably be faster than looping through every file and checking if it's a link.

NevemTeve · 11-04-2014, 11:39 PM

untested:

Code:

readlink * 2>/dev/null | sort -u

find . -type l -print0 | xargs -0 readlink | sort -u

Edit: Oh, forget it, readlink(1) doesn't support multiple files...

(file * | grep 'symbolic link to' would work, though)

The following would work, but requires multiple fork+exec, so it would be slow:

Code:

find . -type l -exec readlink {} \;

a4z · 11-05-2014, 01:05 AM

will check this,
I suspect that find -type l will do the same loop I do, I guess, go through all names, stat each name and check type
I do not run a bash script, I use the C api, but I will measure it there is a difference between my code and find -type l

NevemTeve · 11-05-2014, 02:42 AM

'man find' is my friend:

Code:

find . -type l -printf '%l\n' | sort -u

a4z · 11-05-2014, 05:56 AM

Quote:

Originally Posted by NevemTeve

'man find' is my friend:

Code:

find . -type l -printf '%l\n' | sort -u

this is a very interesting line, thanks

bigearsbilly · 11-05-2014, 09:47 AM

some things are just plain hard work, this is one of them.