Hi,

I'm writing a small bash script. The problem is that sed isn't working as I hope it would.

TEST=h[o]i
echo $TEST > testfile
sed -i "s/$TEST/hoi/" testfile
cat testfile

I would want the result to be hoi and not h[o]i

Does somebody have any nice commend how to solve this problem?

With kind regards,

Maurice Lucas

I can tell you WHY it's happening, but don't have a perfect solution at this time.

Also, any solution or help provided to you, might be particular to a certain version of sed; since you don't tell us what OS this is happening on, and you have posted this question from a Windows machine, it may be relevant if you tell us what OS this problem is occurring on, and which version of sed, as well as the ultimate purpose of this script -- i.e is there an end result that you may be able to accomplish by a different method? Or is this just some homework..

As you may be aware, the [ and ] characters are special characters when using regular expressions, and those characters in your $TEST variable are being expanded and then taken to be parts or a regex, rather than literally.

Two workarounds:

1) check the variable for special characters, and escape them prior to using the variable in the LHS of the sed command.

or

2) Forget about using $TEMP variable, and do the replacement with a literal string, with the special chars escaped.

Sasha

sed --version
GNU sed version 4.1.5

cat /etc/issue
Ubuntu 8.04.4 LTS \n \l

This is a very simplified version of my script. I get a list of Windows directory's on a remote server and I have to check if the backup of every directory did run and is complete.

So i made a "website" which the setup of

dirname resultfield datefield

The sed line will search for the dirname in the html file and change the resultfield in failure/success and a nice color.

I can say they aren't allowed to insert escape characters on that server but it is beter to fix my script that to try t change my client.


The line below is from my real script and does work perfect, as long as tehre aren't any escape characters.
sed -i 's@<tr><td>$RBACKUPDIR.*@<tr><td>$RBACKUPDIR</td><td bgcolor="#FF0000">Failed</td><td>`date +"%A %d %B %Y %H:%M"`</td>@' /var/www/index.html