How to use AWK/SED to insert a line?

Posted on 2008-10-01
Last Modified: 2013-12-26
I have a file that looks like this:



I want to find Fake=Fake and insert another line before it. This change then needs to be written back to the same file. The replacement value is in a variable, say, $__changes

I have been trying sed but for some reason it creates a 0byte file if the source and target files are the same. I am ok if you can provide an awk solution.


cat 'file1.txt' | sed '
/Fake=FakeX/ i\
' > 'file1.txt'

This doesn't work if I try a variable in the replacement text.

Please note I need to insert before only the first instance of the match.

Thanks for your help.
Question by:infa007
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LVL 84

Expert Comment

ID: 22613806
opens and clears the output before sed runs
try sed -i
LVL 84

Expert Comment

ID: 22613869
sed -i.bak -e '/Fake=Fake/ i\
'  file1.txt

Author Comment

ID: 22615073
I get an error: sed: Not a recognized flag: i

Accepted Solution

gisellla_igr earned 500 total points
ID: 22615298
try this

__changes="nueva linea"
cat $file | sed "
/Fake=Fake/ i\\
" > $tmpFile
mv $tmpFile $file

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Author Closing Comment

ID: 31501945
Thanks, exactly what I wanted!

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