Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
How to sort IP addresses in Linux
Answer:
When you have a file ip.txt contains a list of IP addresses, e.g.
127.0.0.2
127.0.0.1
10.10.10.1
To sort it, you can use the following command
# sort -t. -k1,1n -k2,2n -k3,3n -k4,4n ip.txt
10.10.10.1
127.0.0.1
127.0.0.2
How to avoid saving current shell session history
Answer:
It might be happened to your before that you don't want to save the current shell session history, but you don't want to clear all the history by executing "history -c", you can use the following method.
# unset HISTFILE
Logout and type history and you will see last session history was not saved.
Generate random number in Linux
Answer:
To generate a random number from 1 to 100, you can use the following simple command
# echo $((RANDOM%100+1));
76
You can replace 100 by the maximum value, and 1 by the minimum value.
Generate UUID in Linux
Answer:
You can use the uuidgen tool.
E.g.
# uuidgen
6c642ca4-74b4-4090-bacd-2be619ab3c12
Create a temp file in Linux
Answer:
To create a temp file in Linux, you can use the mktemp command
E.g.
# mktemp foo.XXXXXXXXXXX
foo.aAIYdsa5027
mktemp will replace XXXXX... by random characters and create that temp file for you.
