I want to replace \ with \\\\ using sed

Question

I have tried using sed to read \. Unable to read \ and replace it with \\\\. I want to replace single \ with 4 \\\\.

Does this answer your question? Number of backslashes needed for escaping regex backslash on the command-line — Philippos, Feb 01 '22 at 08:52
What have you tried so far? Show us your attempt, as that will help with writing better answers. — Toby Speight, Feb 10 '22 at 15:12

score 3 · Answer 1 · answered Feb 01 '22 at 08:46

3

In a single quoted substitution, use 2 backslash for each literal backslash.

echo '\' | sed 's/\\/\\\\\\\\/'

In a double quoted substitution, you need 4 backslashes for each literal backslash, as the shell interprets each \\ as a backslash.

echo '\' | sed "s/\\\\/\\\\\\\\\\\\\\\\/"

answered Feb 01 '22 at 08:46

choroba

47,233

I used the sed -i 's/\/\\\\/g' filename. It worked. Thanks. – Karishma Feb 01 '22 at 08:56
4

"Thanks" on StackExchange = Upvote / Accept. – choroba Feb 01 '22 at 09:37

Kusalananda · Answer 2 · 2022-02-01T14:52:57.797

sed 's/[\]/&&&&/'

Within [...], which is an expression that matches a single character from the set within the brackets, each \ is literal, so there is no need to escape it (if you use single quotes around the expression; with double quotes, you still have to escape the backslash).

Each of the four & in the replacement string will be replaced by whatever was matched by the regular expression.

Alternatively, if [\] feels weird,

sed 's/\\/&&&&/'

I want to replace \ with \\\\ using sed

2 Answers2