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Old 08-30-2012, 12:50 PM   #1
Registered: Jun 2012
Posts: 47

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Bash - find something in one file and if it doesn't exist in the second file print.

I'm trying to compare two files. I want to grab the first line in the first file and check second file to see if it exists. If it does not exist in second file then print. And so on for every line in file1.

Right now i don't get any output stuck into my output file. I'm sure this is easy and i've just stared at it too long.


while read $line
grep $line $file2 > /dev/null
if [ $? -ne 0 ]; then
echo $line >> output.txt

done < $file1
Old 08-30-2012, 01:06 PM   #2
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while read line

NOT: while read $line

In the first you're declaring the variable which can be used as $line later in the script. In the latter you're attempting to use the variable and likely getting a null since you haven't previously declared it.
Old 08-30-2012, 01:17 PM   #3
Registered: Jun 2012
Posts: 47

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OMG. Well thank you. I was SO freaking close. Always has to be something dumb.


bash, bash scripting

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