在Mac终端中同时使用lsof和awk的奇怪行为？

Question

I want to find all of the lines in lsof with "Google" in them, so I tried the following:

lsof |  awk '/.*google.*/ { print $1 "," $2 "," $3} ' > new_file.csv

which yields correctly an output with rows starting with the word "google".

But, then I try this and the csv contains nothing:

lsof |  awk '/\s*google.*/ { print $1 "," $2 "," $3} ' > new_file.csv

But, I thought that the \\s* means any number of spaces. Is there any reason for this behavior? Thank you.

Answer 1

\\s does mean spaces and \\s* does mean zero-or-more spaces but not in awk.

awk uses a different (older) regex engine.

For awk you want [[:space:]]* to match zero-or-more spaces. (That's a character class class of [:space:] in a character list [] .)

That being said if you just care about google being in the output then you just need /google/ .

If you want an word-anchored google then you want /\\<google\\>/ .

As Ed Morton points out GNU Awk version 4.0+ added support for the \\s metacharacter as well.