Extract number from a line with awk/sed

Question

I have this string:

Stream #0:0: Video: vp6f, yuv420p, 852x478, 1638 kb/s, 25 tbr, 1k tbn, 1k tbc

and I would like to extract 25

Answer 1

Here is one approach with awk:

$ awk '/tbr/{print $1}' RS=, file
25
29.97

Explanation:

By default awk treats each line as a record, By setting RS to , we set the record separator to a comma. The script looks at each record and prints the first field of any record that matches tbr.

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A GNU grep approach that uses positive lookahead:

$ grep -Po '[0-9.]+(?= tbr)' file
25
29.97