How to send email from bash with attachment using standard unix utils

mpack -s "Subject" -c application/octet-stream /home/user/file.zip friends@email.com

How to extract some file from rar archive under bash

rar x archive.rar archives/sql/file.ext /tmp

rar vb archive.rar | grep file

Exclude lines that contains some data with grep

cat test.csv | grep -v -E "(@test.com|12345678909)"

flush squid cache for one site

squidclient -h localhost -p 3128 -m PURGE http://www.example.com