I have a file with a text field that could contain characters the sed sees as special characters.

I need to be able to replace this text with other text, however if I use sed like:

sed 's/oldtext/newtext/g'

It errors stating garbled (something or other), which I am putting down to the fact it is reading the text literally and think the likes of / etc should be treated as special chars.

Is there a way around this so I can get it to ignore what it thinks are special chars? (just see the text - Wow *?/ woopee do /$)

By the way thats not the text I want to add

what does ur input look like and what output ur looking for?

You need to escape the special characters with a backslash, e.g.

echo 'Wow *?/ woopee do /$' | sed 's/Wow \*?\/ woopee do \/\$/replace/'

echo 'Wow *?/ woopee do /$' | sed -r 's/Wow \*\?\/ woopee do \/\$/replace/'

Ygor,

The trouble I have is that the text (both new and old) will be held in variables.

I need to somehow interrogate these variables and add a \ before evry special character.

Any ideas.

Try something like this...

$ search='Wow *?/ woopee do /$'

$ search=$(echo "$search"|sed 's!\([]\*\$\/&[]\)!\\\1!g')

$ echo "$search"
Wow \*?\/ woopee do \/\$

$ echo 'Wow *?/ woopee do /$'|sed "s/$search/replace/"
replace

Thanks Ygor.

Looks like what I am looking for.

With regard ot the sed statement - 's!\([]\*\$\/&[]\)!\\\1!g'

I know what the s and g are, I am also asumming the ! is the delimeter for the sed command. What is the 1 for? and also the chars within the () are they all the possible special characters within SED? I have searched but I cannot find anything about what are special chars in SED.

Also (sorry) one more thing what are the [] for?

I'm sure there are more including ^.

If you have perl, perl has a nice feature to deal with special characters.

perl -pe   "s/\Q$search\E/replace/"