Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Wrap each line to fit in specified width
Answer:
If you want to format a text file into a specific width, you can use the fold command
E.g.
# fold -w 40 test.txt
The above command will wrap the text file and print to standard out, with width = 40 characters.
How to bulk rename files in Linux
Answer:
Use the rename tool
E.g.
# rename .htm .html *.htm
The above command will rename all *.htm files to *.html files.
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.
