How to delete a file securely in Linux

For deleting a file securely in Linux use any of the following commands
$ srm filename
read man srm for more details
or you can use wipe utility
$ wipe filename
The most popular one is shred available with most distributions
$ shred -n 200 -z -u personalinfo.tar.gz
-n -overwrite 200 times
z: Add a final overwrite with zeros to hide shreddin
-u: Truncate and remove file after overwriting
You can download srm and wipe from from
http://sourceforge.net/projects/srm
http://wipe.sourceforge.net/