I am trying to remove a given line $2 from the file /root/.ssh/authorized_keys using sed. Here is the command I am running, unfortunately, its not deleting the line. Any idea what I'm doing wrong?
sed -i '/$2/d' /root/.ssh/authorized_keys
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Are you seeing an error message? Do you have write access to the file?martin clayton– martin clayton2011-09-08 23:56:43 +00:00Commented Sep 8, 2011 at 23:56
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3 Answers
$2 won't be replaced with its value inside single quotes. Should work with double quotes.
3 Comments
teambob
sed -i "/$2/d" /root/.ssh/authorized_keys
Justin
Getting an error from sed.
sed: -e expression #1, char 41: unknown command: 3'' Probably because the public key, has special sed characters in it. Is there a way to quote it?
holygeek
Use a non-base64 valid character as sed's separator, something like this should work: sed -i "\,$2,d"
Posting a non-sed answer as suggested by Glenn Jackman. The basic "right answer" was already posted by Tom Zych; note also the comment by holygeek.
mv authorized_keys authorized_keys~
fgrep -v "$2" authorized_keys~ >authorized_keys
You could probably get by without the temporary file but I'm not at my computer so I'm playing it safe for now.
Comments
You can also use the shell
while read -r line
do
case "$line" in
*"$2"* ) continue;;
* ) echo "$line" ;;
esac
done < /root/.ssh/authorized_keys > tempfile
mv tempfile /root/.ssh/authorized_keys
answered Sep 9, 2011 at 2:12
5 Comments
tripleee
More like
fgrep -v "$2" authorized_keys ...!
bash-o-logist
To the one who downvote, make sure you know why you downvote.
glenn jackman
@tripleee, you might want to put that comment as an answer. It's the best answer I see here.
Justin
I tried
fgrep -v "$2" /root/.ssh/authorized_keys > /root/.ssh/authorized_keys and it just clears out the entire authorized_keys file.tripleee
Yeah, you cannot redirect into the file you want to read from, you need a temporary file or some other workaround.