Question

I have several files containing this line

Release: X 

I want to increment X in all the files.

If X was constant between the files, I could have a bash script looping around the files and doing ($1 containing the former release number and $2 the new one, ie. $1 + 1) :

sed 's/Release: '$1'/Release: '$2'/' <$file >$file.new 

Now, how should I do if the release number is different between files ?

Is it doable with sed ?

should I use another tool ?

Answer 1

Use awk – it’s exactly the right tool for this:

awk '/Release: [0-9]+/ { printf 'Release: %d\n', $2+1 }' < $file > $file.new 

Translation:

• Search for lines that contain ‘Release: ‘ followed by one or more digits.
• Print ‘Release: ‘ followed by a number and a newline. The number is the second word in the input line (the digits), plus 1.