CODEWITHSUNDEEP
linuxbashunixsed
shd
shd

Reputation: 1119

sed with special characters

I have this line that I want to use sed on:

--> ASD = $start ( *.cpp ) <--

where $start is not a varaiable, I want to use sed on it and replace all this line with:

ASD = $dsadad ( .cpp )

How can I make sed ignore special charactars, I tried adding back slash before special characters, but maybe I got it wrong, can some one show me an example?

Here is what i want :

sed 's/CPPS = \$(shell ls | grep \*\.cpp )/somereplace/' Makefile

Upvotes: 14

Views: 86776

Answers (4)

Sheikh Aafaq Rashid
Sheikh Aafaq Rashid

Reputation: 199

I have one use case where I have to replace a text with a variable, that variable contains a special symbol, like ([email protected]). This @ symbol was creating an issue. So I found this solution useful.

SERVICE_ACCOUNT="[email protected]"
sed -i 's/DEVOPS_SERVICE_ACCOUNT/'${SERVICE_ACCOUNT}'/g' file.txt

Upvotes: 0

glenn jackman
glenn jackman

Reputation: 246764

The chacters $,*,. are special for regular expressions, so they need to be escaped to be taken literally.

sed 's/ASD = \$start ( \*\.cpp )/ASD = \$dsadad ( .cpp )/' somefile

Upvotes: 1

C&#233;dric Julien
C&#233;dric Julien

Reputation: 80761

sed 's/\$start/\$dsadad/g' your_file
>> ASD = $dsadad ( *.cpp ) 

sed 's/\*//g' your_file
>> ASD = $start ( .cpp )

To follow your edit :

sed -i 's/ASD = \$start ( \*.cpp )/ASD = \$dsadad ( .cpp )/' somefile
>> ASD = $dsadad ( .cpp )

Add the -i (--inplace) to edit the input file.

Upvotes: 7

sapht
sapht

Reputation: 2829

Backslash works fine. echo '*.cpp' | sed 's/\*//' => .cpp

If you're in a shell, you might need to double escape $, since it's a special character both for the shell (variable expansion) and for sed (end of line)

echo '$.cpp' | sed "s/\\$//" or echo '$.cpp' | sed 's/\$//' => '.cpp'

Do not escape ( or ); that will actually make them them special (groups) in sed. Some other common characters include [ ] \ . ?

This is how to escape your example:

sed 's/ASD = \$start ( \*\.cpp )/ASD = $dsadad ( .cpp )/' somefile

Upvotes: 4

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