Friday, August 24, 2012

How to delete empty files directories in Unix Linux Server

Deleting empty file and directory in Unix
Many times we need to find and delete empty files or directories in UNIX/Linux. Since there is no single command in Unix/Linux which allows you to remove empty files or empty directories rather we need to rely on find command and xargs command. In this UNIX and linux example we will see How to delete empty files and directories. Before removing empty files and directories we need to find those files and there are lots of option available to search for empty directories like find, grep , awk etc. You just need to know correct option. Like in any other operating system empty files and directories in Unix are those whose size is zero. Empty files doesn't contains any content while empty directories does not contain anything at all e.g files or sub-directories. As discussed in previous post 10 frequently used  find command examples we can also use find command to search and delete empty files and directories as it provides searching files based on size as well.



Creating Empty files and directories in Unix
How to remove empty files and directories in Unix and Linuxlet's first create empty file and directory to demonstrate example of how to delete empty files in Unix. We can use same set of commands which we have used in our example of How to find size of files and directories in Unix.

//This will create empty file in current directory
test@localhost:~/unix touch empty.txt          

//This will create empty directory inside current directory
test@localhost:~/unix mkdir empty_dir    

//This command will find all empty files and directories in Unix
test@localhost:~/unix find . -empty          
./empty.txt
./empty_dir


Searching Empty Files and Directory in Unix/Linux

find -empty option prints both empty files and directories. If you just want to print files than use -type f option and -type d for listing empty directories. its quite flexible. You can also use grep command along with ls –lrt to display empty files and directories as shown below :

//this command will print empty files
test@localhost:~/unix find . -type f -empty
./empty.txt


//this command will print empty directories
test@localhost:~/unix find  . -type d -empty
./empty_dir


//How to use grep command to print empty files and directories
test@localhost:~/unix ls -ltr | grep '\<0\>'
drwxr-xr-x+ 1 test Domain Users   0 Jun 15 11:43 empty_dir/
-rw-r--r--  1 test Domain Users   0 Jun 15 11:44 empty.txt

//find command to print empty files and directories
test@localhost:~/unix find . -maxdepth 1  -size 0 -ls
90353467524120775    0 drwxr-xr-x   1 test Domain Users        0 Jun 15 11:43 .
9007199255261921     0 -rw-r--r--   1 test Domain Users        0 Jun 15 11:44 ./empty.txt
19421773393554899    0 drwxr-xr-x   1 test Domain Users        0 Jun 15 11:43 ./empty_dir

Deleting Empty Files and  Directories in Unix Linux
Now once we certain that there are empty files and directory exists you can delete them by using find -delete option or executing rm command in combination with find command as shown below:

//removing Empty files and directories using find command
test@localhost:~/unix find . -empty -delete

test@localhost:~/unix find . -empty -delete

test@localhost:~/unix ls -lrt
total 1.0K
-rw-r--r-- 1 test Domain Users 118 Aug  4  2011 contacts.txt

//using find and xargs command to remove empty files and directories
test@localhost:~/unix find . -empty | xargs rm -r

test@localhost:~/unix find . -empty -type d -exec rm -r {} \;
find: `./empty_dir': Not a directory


That’s all on How to find and remove empty files and directories in Unix and Linux host. As I mentioned there are many ways to find empty files and directory but best way is by using find command, which not only list empty files but empty directories as well.

Other Unix and Linux command tutorials from Javarevisited Blog

2 comments :

deeps said...

Very nice article..very helpful for interviews..
As you mentioned there are lot of ways to delete files and directories, just wanted to add on one more way:

rm -rf `find . -empty`

yuanca said...

I've been using find for ages but this is the first time to hear about -empty and -delete. (Later GNU additions?) Thanks!

But the premise in this fine article is incorrect. Why would "find . -empty -delete" or "find . -empty -exec rm -r {} \;" not be counted as a "single command"?

Second, "find . -empty -delete" or its -exec equivalent is better than xargs and backquote when you have many to delete. The problem with a second command is that each command can only take this many arguments in shell. So when find finds too many empty files, the second command will bail with error message "Too many arguments." Now the rm from within -exec actually receives only a single argument each time find finds a file or directory, so there is no fuss about too many of them.

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