How to encrypt a file in linux

# vim test.txt (write something here)

This is a Test file

:wq
Now see the Content of the file using cat command

# cat test.txt

This is Test file

Now we are going to Encrypt the file with gpg

# gpg -c test.txt

Enter Pass-phrase : <YOUR-PASSWORD>
Repeat Pass-phrase : <YOUR-PASSWORD>

You can see one more file create

# 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

# cat test.txt.gpg
i+`P$@CoEkW%>o
8*zbB`EA9{7
IW

Delete original File

# rm test.txt

Now we are going to decrypt the encrypted file

# gpg test.txt.gpg
Enter Pass-phrase : <YOUR-PASSWORD>

See decrypted file content

# cat test.txt
This is a Test file