How to Encrypt a file in Linux

root@user:~# vim test.txt (write something here)

This is a Test file

:wq
=====Now see the Content of the file using cat command=====
#root@user:~# cat test.txt
This is Test file

=====Now we are going to Encrypt the file with gpg======
root@user:~# gpg -c test.txt

Enter Pass-phrase :

Repeat Pass-phrase :

====You can see one more file create.=====
root@user:~# ls -l test*

-rw-rr 1 root root 59 2011-03-02 17:20 test.txt
-rw-rr 1 root root 97 2011-03-02 17:23 test.txt.gpg

=====Lets try to see encrypt file with cat command=====
root@user:~# cat test.txt.gpg

i+`P$@CoEkW%>o
8*zbB`EA9{7
IW

=====Delete original File=====
root@user:~# rm test.txt
=====Now we are going to decrypt the encrypted file=====
root@user:~# gpg test.txt.gpg

Enter Pass-phrase :
=====See decrypted file content=====
root@user:~# cat test.txt
This is a Test file