Capturing or cutting few characters of a string
Posted by Vivek Gite
[Last updated: May 2, 2006]
Shell scripting is part of my day today life job. Sometime you just need to cut or grab first few characters of a string. For example, consider following string I am using in a script:
IP=”192.168.1.5”
CONF=”something”
I just need to grab network id i.e. 192.168.1 of a string $IP
I can write out
$ test=${IP:0:9}
$ echo $test
It took me more than an hour to find out solution to this tiny problem. BASH man page Parameter Expansion has lots of information. Make sure you read it.
Tell us how we're doing: Please answer a few questions about your experience to help us improve nixCraft.
You may also be interested in other helpful articles:
- How do I replace text string in many files at once?
- Shell scripting (BASH) : How to accept password in script
- Shell scripting tip: Find the length of a string under UNIX / Linux oses
- Linux check passwords against a dictionary attack
- Shell scripting and brace expansion
Discussion on This Article:
Leave a Reply
We encourage your comments, and suggestions. But please stay on topic, be polite, and avoid spam. Thank you very much for stopping by our site!
dude,
you need to use either CUT or some other mechanism.
since your script will need tweaking to handle Network IP like
192.168.128.1
use AWK/GAWK/CUT to split the network address into four parts using “.” as operator.
and then concatenate and use first three.
hi,
it can be written in other ways
$ echo $IP | cut -f1-3 -d”.”
this works fine…