Programming Forums - if condition and grep

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- - if condition and grep (http://www.programmingforums.org/showthread.php?t=15879)

nuvox

May 25th, 2008 7:39 AM

if condition and grep

hey all

im trying to write a script, need some help

concept goes like this: i want to grep a file for a word/phrase, and depending on grep's output (basically, any output at all = found, NULL = not found) to do -something-.

basically, in pseudocode:

if(grep_output == NULL):

    echo "not found";

else:

    echo "found"

could someone point me in the right direction? thanks in advance!

nuvox

May 25th, 2008 9:29 AM

Re: if condition and grep

okay, figured it out.

grep_output=`grep <word> <file>`

if [ "$grep_output" == "" ]; then

    echo "not found";

else

    echo "found";

fi

Jessehk

May 25th, 2008 9:38 AM

Re: if condition and grep

#!/bin/bash
 
if grep "found" "example.sh" > /dev/null; then
    echo "Found"
else
    echo "Not found"
fi

gromit

Sep 9th, 2008 1:23 AM

Re: if condition and grep

More streamlining! :)

#!/bin/bash

if grep -q "found" "example.sh" ; then

    echo "Found"

else

    echo "Not found"

fi

Or if you want to have the grep output in a variable to manipulate it later, here's a tidier version of your original example (your original example will work fine, some of us just like to tweak ;)

#!/bin/bash

if [ $# -ne 2 ] ; then

  echo "usage: $0 <word> <file>"

fi



grep_output="$(grep $1 $2)"



if [ -z "$grep_output" ]; then

    echo "not found";

else

    echo "found";

fi

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