How to replace quotation marks in a file with sed?

Question

I have a file that contains multiple lines of xml. I would like to replace certain parts of the file. Some parts of the file contains quotation marks (") which I would like to replace. I have been trying to escape the quotation mark with \, but I don't think this is working based on the result of my file.

Here is an example of one of my sed commands:

sed -e "s/\"text\"/'text'/ig" file.xml > temp.tmp

Is this how you escape quotation marks in a sed command or am I doing something wrong?

Answer 1

Two tips in Bourne-like shells:

1. You can't escape a single quote within a string quoted with single quotes¹. So you have to close the quote, add an escaped quote, then open the quotes again. That is: 'foo'\''bar', which breaks down as:

   • 'foo'        quoted foo
   • \'             escaped '
   • 'bar'        quoted bar

   yielding foo'bar.

2. (optional) You don't necessarily have to use / in sed. I find that using / and \ in the same sed expression makes it difficult to read.

For example, to remove the quotes from this file:

$ cat /tmp/f
aaa"bbb"'ccc'aaa

Given my two tips above, the command you can use to remove both double and single quotes is:

$ sed -e 's|["'\'']||g'  /tmp/f

Based on my first tip, the shell reduces sed's second argument (i.e., the string after the -e) to s|["']||g and passes that string to sed. Based on my second tip, sed treats this the same as s/['"]//g. It means

remove all characters matching either ' or "   (i.e., replace them with nothing)

You probably need something more complex than this to do what you want, but it's a start.

---

^{¹ Except in zsh (primarily a Bourne/Korn-like shell even though it does also have a few features from csh/tcsh (like bash) and rc) when the rcquotes option is enabled after which you can escape single quotes as '' like in the rc shell or derivatives, as in echo 'There''s a single quote in that single-quoted string'.}

Answer 2

I have a Windows port of unix utilities so commands look a bit different but I had a csv file with commas and quote marks. Using this thread as a guide, I was able to remove the quotes via this command:

c:\Temp> cat report.csv | sed "s/\,/\ /g" | sed "s/[""]//g"

Answer 3

Use a quantifier (+) ater the double quote in the search side only.

The question mark (?) is also a quantifier but makes optional, it could be used if you want the quote in the result even if the search has or not a quote at that position (?).

The general answer is using ("+) that means "at least one".

 sed -i -E 's/text"+hi/text"no/g' onefile

 # will change text"hi by text"no