[SOLVED] sed: variable in a search string

thealmightyos · 04-03-2014, 11:33 AM

High all! Having a little issue with sed and wondering if anyone has some insight

What I am trying to do: find all instances of "00/00/0000" within a file and replace with the current date. This is within a batch file with a variable for current date ($date).

Here is my code:

Code:

sed -i 's/\00\/00\/2000/"${date}"/g' /file.txt

What's happening:
The file is edited. All instances of "00/00/0000" have been replaced with ""${date}"".

What am I missing?

colucix · 04-03-2014, 11:39 AM

The double quotes inside single quotes are interpreted literally and the variable expansion is not performed. You can always embed the whole sed command in double quotes (until there is no ambiguity for the shell), e.g.

Code:

sed -i "s/00\/00\/2000/${date}/g" /file.txt

Also take in mind that you can use any character as separator in the s command. This is useful when the regular expression or the replacement string contain slashes:

Code:

sed -i "s:00/00/2000:${date}:g" /file.txt

thealmightyos · 04-04-2014, 10:42 AM

Quote:

Originally Posted by colucix

The double quotes inside single quotes are interpreted literally and the variable expansion is not performed. You can always embed the whole sed command in double quotes (until there is no ambiguity for the shell), e.g.

Code:

sed -i "s/00\/00\/2000/${date}/g" /file.txt

Also take in mind that you can use any character as separator in the s command. This is useful when the regular expression or the replacement string contain slashes:

Code:

sed -i "s:00/00/2000:${date}:g" /file.txt

That worked! I always mess up where to put the quotes at and if I should use a single or a double. Programmer I am not.

Thanks for the help