awk command with search string variable

Question

Configuration.xml has "mysearchstring" at position (line) 23.

If I use the following statement, it returns me line 23

awk '/"mysearchstring"/{print NR}' Configuration.xml

But if I use an assigned variable, it returns me nothing

str="mySearchString";awk '/$str/{print NR}' Configuration.xml

Can someone tell me what is incorrect in the second statement?

I am using a bash shell to execute this, so the option given about will not work... — user1651888
– user1651888, Commented Feb 25, 2014 at 13:08
Also if there are 3 lines maching, I would like to get only the first line number. — user1651888
– user1651888, Commented Feb 25, 2014 at 13:14
Update your question with a proper explanation instead of commenting here in the comments. — fedorqui
– fedorqui, Commented Feb 25, 2014 at 13:33

fedorqui · Accepted Answer · 2014-02-25 12:55:13Z

2

You need to pass the variable to awk with -v and then use the ~ comparison:

awk -v myvar="$str" '$0 ~ myvar {print NR}' Configuration.xml

$ cat a
hello
how
are 
you

$ awk '/e/ {print NR}' a <---- hardcoded
1
3

$ awk -v myvar="e" '$0~myvar {print NR}' a <---- through variable
1
3

answered Feb 25, 2014 at 12:55

fedorqui

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Comments

Arkku · Accepted Answer · 2014-02-25 12:57:05Z

1

You can use the command-line option -v to pass variables to awk:

awk -v searchstr="$str" '$0 ~ searchstr { print NR }'

answered Feb 25, 2014 at 12:57

Arkku

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Jotne · Accepted Answer · 2014-02-25 13:12:29Z

0

Or you can pass variable like this, after code:

awk '$0~s {print NR}' s="$str" file

answered Feb 25, 2014 at 13:12

Jotne

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