Linux Ask!

Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.

Move cursor to the end of line in VIM

Answer:

To move to the end of a line in VIM, type

$

You can also type "A" to append at end of the line.

Move cursor to the end of file in VIM

Answer:

To move to the end of a file in VIM, type

G

Removed opened port in ufw

Answer:

If you have opened a port using the ufw command in Ubuntu, but now you want to delete it, you can..

# sudo ufw delete allow 8080/tcp

And then do a reload

# # sudo ufw reload

That's all.

How to perform a reverse DNS lookup in Linux

Answer:

To perform a reverse DNS lookup for a domain in Linux, you can use the dig command, e.g.

# dig -x 8.8.8.8

; <<>> DiG 9.7.0-P1 <<>> -x 8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59808
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;8.8.8.8.in-addr.arpa.          IN      PTR

;; ANSWER SECTION:
8.8.8.8.in-addr.arpa.   86328   IN      PTR     google-public-dns-a.google.com.

..

Exclude files when using the du to estimate disk usage

Answer:

It is easy to use du command to estimate disk usage, however, sometimes you want to ignore some files during the calculation.

To do so, try

# du -h --exclude='*.bak'

The above command will exclude all the file end with the extension .bak during the disk space calculation.