How do I replace a comma to "\," in a string using sed

Question

I have a string in which I need to replace "," with "\," using shell script. I thought I can use sed to do this but no luck.

Answer 1

You can do that without sed:

string="${string/,/\\,}"

To replace all occurrences of "," use this:

string="${string//,/\\,}"

Example:

#!/bin/bash
string="Hello,World"
string="${string/,/\\,}"
echo "$string"

Output:

Hello\,World

Answer 2

You need to escape the back slash \/
I'm not sure what your input is but this will work:

echo "teste,test" |sed  's/,/\\/g'

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output:

teste\test

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Demo: http://ideone.com/JUTp1X

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If the string is on a file, you can use:

sed -i 's/,/\//g' myfile.txt