How to replace to apostrophe ' inside a file using SED

Question

I have a file "test.txt" that contain the following

+foo+
+bar+

What I want to do is to replace them into:

'foo'
'bar'

But why this code doesn't work?

sed  's/\+/\'/' test.txt

What's the right way to do it?

score 25 · Accepted Answer · answered Aug 08 '13 at 06:40

25

Use " instead. And add g flag to replace all.

sed  "s/\+/\'/g" test.txt

answered Aug 08 '13 at 06:40

falsetru

sed "s/\$/\'/g" ut.txt - this is adding ' at the end instead replacing the $ character. am i missing something? – Anu Jul 04 '17 at 10:55
As [anubhava](https://stackoverflow.com/a/18119525) mentions, `+` is not a metacharacter without the `-r` option, thus `sed "s/+/'/g" test.txt` should do the trick. – thymaro Apr 19 '21 at 06:41

score 5 · Answer 2 · answered Aug 08 '13 at 07:38

5

This might work for yoyu (GNU sed):

sed 'y/+/'\''/' file

answered Aug 08 '13 at 07:38

potong

score 3 · Answer 3 · answered Aug 08 '13 at 06:44

3

+ is not a special character without -r switch in sed. You can run the substitute command without any escaping:

echo '+foo+' | sed "s/+/'/g"

# output: 'foo'

If you want to save changed file then use:

sed -i.bak "s/+/'/g" test.txt

answered Aug 08 '13 at 06:44

anubhava

devnull · Answer 4 · 2013-08-08T09:35:05.283

3

You can also replace all instances of + with ' in the file by using tr:

tr '+' "'" < inputfile

edited Aug 08 '13 at 09:35

answered Aug 08 '13 at 06:47

devnull

4 Answers4