Table of Contents
In this post, we will see how to use awk substr to select substring.
awk command has a lot of useful functions. One of them is awk substr function.
awk substr function is useful to select substring from a string.
Syntax
Where String is input string.
x is starting position in string(index starts from 1)
y is number of characters starting from x (optional)
Let’s create a test file.
$ cat > test.txt
This is sample file
Let’s see some awk substr examples on above created file.
$awk ‘{print substr($1,1,1)}’ test.txt
T
awk ‘{print substr($3,3)}’ test.txt
mple
awk ‘{print substr($4,1,2)}’ test.txt
fi
awk ‘{print substr($0,9,6)}’ test.txt
sample
Let’s create another sample file
You can search text and apply substr on the result as well.
For example:
$ cat > test2.txt
Welcome to java2blog
This is sample file,thanks
Let’s search for “sample file” and print “thanks” from the result.
$ awk ‘/sample file/{print substr($4,6)}’ test2.txt
thanks
We have searched using ‘/text to be searched’/ and then applied substr function on the result.
That’s all about awk substr function.