Replacing variable containing \ with sed

Question

i am trying to replace $old string with $new string in file where:

old=ESX_10.1.1.1\@11.11.11.11
new=host_15_11_0_111.static

I am using sed command:

sed i "s/${old}/${new}/g" /filename

but it does not replace the word and also not shows any error. I have tried it with many ways, like replacing:

sed i "s,${old},${new},g" /filename

and

sed i "s=${old}=${new}=g" /filename

but it does not work. Help me to solve this

See How to ensure that string interpolated into `sed` substitution escapes all metachars — Stéphane Chazelas, Jun 10 '16 at 06:22

score 1 · Answer 1 · answered Jun 10 '16 at 06:20

1

You need to escape the \ with another \. You can do this in a bash shell variable as follows

sed -i -e "s/${old//\\/\\\\}/${new//\\/\\\\}/g" filename

See man bash Parameter Expansion for ${parameter/pattern/string}. We use the version with // instead of / to do it repeatedly. And we need to escape \ with itself, so it gets duplicated a lot.

answered Jun 10 '16 at 06:20

meuh

51,383

"s/${old//\\/\\\\}/${new}/g" should work too as in this case new variable doesn't have backslashes to escape – Sundeep Jun 10 '16 at 06:26
Hi tried with s/${old//\/\\}/${new}/g but it gives error,"sed: -e expression #1, char 2: unterminated `s' command" – Rockey Jun 13 '16 at 04:29
Note you must be using bash as your shell. You can add set -x to the start of the script so you can see what strings are actually being used. You must the double-quote char " as shown in the sed, and also when setting your variable old="ESX_10.1.1.1\@11.11.11.11". – meuh Jun 13 '16 at 05:41

Replacing variable containing \ with sed

1 Answers1