Tag: Perl

Convert Squid/timestamps to a human readable format

Somebody had the brilliant idea of using Unix timestamps in Squid log files. It makes parsing easy but reading them is not so human-friendly.

This is an elegant way of solving the problem:

cat /var/log/squid/access.log | perl -p -e 's/^([0-9]*)/"[" . localtime($1) . "]"/e'

The Perl one-liner captures the timestamp at the beginning of each line, converts it to a human-readable date with localtime(), and replaces it inline. The /e flag tells Perl to evaluate the replacement as code rather than a string.

Hope it helps!

Remove all non-ascii characters with perl

Sometimes when creating one-liners, the source contains non-ASCII characters that make parsing harder. To strip them all out, use Perl:

cat dirty-source.txt | perl -pe 's/[^[:ascii:]]//g' > clean-output.txt

This replaces every character that is not in the ASCII set with nothing, leaving only clean ASCII text. The same approach works for Windows line endings or other invisible characters by adjusting the character class.

If you prefer a sed alternative for the same task:

sed 's/[^[:print:]]//g' dirty-source.txt > clean-output.txt

Hope it helps!