For Perl one-liners, when using the -p or -n flags is it possible to make the END {} block execute once per file, instead of only once for the entire program?
In other words, when I write:
perl -ne '$count++ if/.../; END {print "$ARGV: $count" if $count > 0}' mysourcedir/*.html
I’d like to execute the END block once for each file, instead of just once globally at the end of the program’s execution.
Currently I just use xargs for this, but wondered if Perl maybe had some alternate flag for that behavior.
echo mysourcedir/*.html | xargs -n1 perl -ne '$count++ if/.../; END {print "$ARGV: $count" if $count > 0}'
PS – in case you’re wondering why I don’t just just grep | wc -l for this simple case, it’s because this example is simplified from my real use case, which involves both incr (++) as well as decr (–) in the tally
Answer: Based on @mpapec’s technique, plus a small tweak to also reset the $count var per file, I get this which works:
perl -ne '$count++ if/.../; if (eof && $count > 0) {print "$ARGV: $count"; $count = 0;} ' mysourcedir/*.html
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Answer
You can check eof for end of each file,
perl -ne '$count++ if/.../; eof && sub{ print "$ARGV: $count" if $count > 0 }->()' mysourcedir/*.html
or
perl -ne '$count++ if/.../; eof && do{ print "$ARGV: $count" if $count > 0 }' mysourcedir/*.html