Bash Scripting- Grep/Awk output as input to another script

Question

I have a script that runs against a file and that takes arguments from a user and is sent through grep and awk to get the desired column. It will return multiple lines. What I want to do is read (or something of the like) through the output from grep|awk and run that through another script (./lookup). My question is how can I loop through each line and run what is on that line through my script inside the script. Hope this makes sense, I'm new to scripting and linux.

#!/bin/sh
x=$(grep "$*" "$c"|awk '{print $6}')
while read LINE   
do
./lookup $x
done

This seems to work but only for the first line of the output. It also requires me to hit enter to get the output from the ./lookup script. Any ideas or help? Thanks!

Barmar · Accepted Answer · 2014-10-01 05:27:11Z

1

Pipe the output of grep and awk to the loop:

grep "$*" "$c" | awk '{print $6}' | while read LINE
do
    ./lookup "$LINE"
done

BTW, it's not usually necessary to use both grep and awk, since awk can do regexp matching. So you can write:

awk -v re="$*" '$0 ~ re {print $6}' "$c" | while ...

The -v option sets an awk variable, and the ~ operator performs regular expression matching. $0 refers to the whole input line.

edited Oct 1, 2014 at 5:27

answered Oct 1, 2014 at 5:22

Barmar

789k57 gold badges555 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

luqui Over a year ago

I think $* here is referring to the list of arguments, which will be interpolated by the shell

swam Over a year ago

I didn't realize that, thank you! My reasoning for the use of $* was in case more than one word was entered as an argument against the main script (./find Los Angeles). Is there an easier way to make sure the whole string is passed?

Barmar Over a year ago

Usually users are expected to enclose the argument in quotes, e.g. ./find 'Los Angeles'.

user3442743 · Accepted Answer · 2014-10-01 07:27:52Z

1

You could also use xargs instead of a loop

Also as barmar stated there is not need for grep.

awk -va="$*" '$0~a{print $6}' "$C" | xargs ./lookup

answered Oct 1, 2014 at 7:27

user3442743

Collectives™ on Stack Overflow

Bash Scripting- Grep/Awk output as input to another script

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related