How to replace string containing / in a text file

tikit · 09-05-2008, 03:43 AM

Hi,

I am trying to write a script, that replaces string in a text file.

I used

Code:

sed 's/find/replace/g' oldfile > newfile

It works fine, but if the string contains '/' character I get this

Code:

sed 's/tpoWYH/.CrDts/newstring/g' oldfile > newfile
sed: -e expression #1, char 17: unknown option to `s'

Is there any way how to replace this string?

Thanks for your help

tikit

theYinYeti · 09-05-2008, 03:49 AM

You can either change the separator:

Code:

sed 's#tpoWYH/.CrDts#newstring#g' oldfile > newfile

or escape the offending character:

Code:

sed 's/tpoWYH\/.CrDts/newstring/g' oldfile > newfile

Yves.

tikit · 09-05-2008, 08:38 AM

Thanks for help. I have another problem. If I use

Code:

sed 's:$old_string:$new_string:g' oldfile > newfile

where $old_string and $new_string are variables containing the string, it does not work. The both variables contain the right string, I checked it using

Code:

echo $old_string $new_string.

. I think sed does not deal with $old_string and $new_string as being variables, bacause it worked if I replaced the variables with the real strings.

Thanks for help

tikit

colucix · 09-05-2008, 08:45 AM

The sed command is embedded in single quotes: this prevents the shell variable expansion and the items $old_string and $new_string are passed literally. Try to run without quotes:

Code:

sed s:$old_string:$new_string:g oldfile > newfile

the usage of single quotes is not really needed, unless you have something you want to protect from shell expansion.

chrism01 · 09-05-2008, 08:48 AM

double quotes works for me:

sed -i -e "s:$a:$b:" filename

single quotes prevent variable interpolation/substitution