my 2009 solution return code before grep ( ( ( mycmd echo $? >&3 ) |grep mytext >&4 ) 3>&1 |(read x;exit $x) )4>&1 my 2025 solution mycmd > >(grep mytext)
Tag: UNIX
negative regexp
if you want to grep anything except foo, use grep -v or negative lookahead echo -e ‘foo\nbar\nboz’|grep -P ‘^(?!.*foo).*$’ bar boz it is just so beautiful ! e.g. get IP address except localhost in /etc/hosts grep -Po ‘^(?!127.0.0.1)[0-9.]+’ /etc/hosts 192.168.1.1 192.168.1.2 if you have no grep -P, use perl
cp -r preserves links
Linux is not Unix, I keep finding out differences years after years. I’ve been using cp -r for over 25 years to find out today, the good old cp -r is cp -Lr on Linux. e.g. AIX $ touch foo $ ln -s foo bar $ cp -r bar boz $ ls -la boz -rw-r–r– […]