UNIX for Dummies Questions & Answers

OS Platform : Oracle Linux 6.5

We are creating a shell script to purge old log files . It uses find command with rm in it.

The syntax is

find <Path of Log Directory> -exec rm -fr {} \;

Example:

find /tmp/test3 -exec rm -fr {} \;


For rm command , we use -r option to remove directories because it is not just files we want to delete. We have to purge directories too. Because sometimes our application creates directories for certain type of issues. For example, when the application crashes, it creates a 'Core Dump' directory by which several files are clubbed together and placed in a coreDump directory . Example coreDump_29_June_2015_11_05_32.

But, I have noticed that, when we try to search for files and directories in the search path, find command is returning the search path too in the result set. For example , I am trying to find all files and directories within /tmp/test3 directory . But, find is returning "/tmp/test3" in the result set too (shown in red below )

Since find is falsely returning the search path itself, rm is trying to remove it. But, rm is trying to delete a directory called
"/tmp/test3" within /tmp/test3 . ie. rm /tmp/test3/tmp/test3 which doesn't exist. So, it is harmless. But, how can I prevent the find command from returning the search path itself (the line shown in red below).

Code:

$ mkdir test3
$
$
$ cd test3
$
$ pwd
/tmp/test3
$ touch abc{1,2,3}.txt
$

## BTW.. Following command will work even without -print option

$ find /tmp/test3 -print
/tmp/test3
/tmp/test3/abc2.txt
/tmp/test3/abc3.txt
/tmp/test3/abc1.txt

$ find /tmp/test3 -exec rm -f {} \;
rm: cannot remove `/tmp/test3': Is a directory
$
$ ls
$
$ ls -lt
total 0
$
$ find /tmp/test3 -exec rm -fr {} \;
find: `/tmp/test3': No such file or directory
$
$ ls
$
$ pwd
/tmp/test3

Code:

rm: cannot remove `/tmp/test3': Is a directory

fails not because a directory tmp/test3 doesn't exist in /tmp/test3 (it is an absolute path, see the leading "/") but because you skipped the -r option.

---------- Post updated at 16:07 ---------- Previous update was at 16:03 ----------

And, you may want to give

Code:

find /tmp/test3/* -print

a shot.

Thank You Rudic.
I did try -r as shown in my first post

Code:

$ find /tmp/test3 -exec rm -fr {} \; 
find: `/tmp/test3': No such file or directory

WARNING!

If you have a symbolic link under /tmp/test3 that points to anywhere else, then find may follow it and do untold damage.

Do not risk testing it.


You can limit the damage a little if you use the -xdev flag on the find command, but that just stops is jumping out the file-system.



Robin

I may shed light onto some of your troubles:

Code:

## BTW.. Following command will work even without -print option

$ find /tmp/test3 -print

Yes, because "-print" is the default clause if no other one is given. When you write it out you just manually recreate the default. I suppose it is in the man page, it is definitely on the POSIX description:

Code:

$ find /tmp/test3 -exec rm -fr {} \; 
find: `/tmp/test3': No such file or directory

Yes, look at the output of your command when you used the "-print" instead of "-exec": the first directory to be listed was - "/tmp/test3", yes? Now, what string do you suppose has gone first into "rm -rf", hmmm? What will a rm -rf /tmp/test3 do to a file /tmp/test3/file or to a directory /tmp/test3/directory or to a file /tmp/test3/directory/file in it?

What you see is "find" being a bit dumbfounded by the fact that the directory structure it was just starting to read is already gone. Your prompt shows "/tmp/test3" being the current directory, but this is just because the shell hasn't noticed now that the directory is already gone. Do a "cd *" and you will probably find that "/tmp/test doesn't exist any more.

This is absolutely true and a valuable advice you should take to heart! It might not be necessary because of the reasons above - before find could even try to follow a link it will already be long gone - but beware once you got your command halfways correct and it starts actually doing what you mean (which might not be what you want).

Fortunately there is a remedy:

Code:

find /tmp/test3/* -prune ! -type l -exec rm -rf {} \;

Because you use rm -r you do not need to descend the directory structure at all, the first layer will suffice. All links are filtered out before find gets to the dangerous stuff.

I hope this helps.

bakunin