1. Bash scripting OpenFest Gabrovo 2010 Marian Marinov System Architect at Siteground.com

2. 1. What will save time if cmd; then echo OK; fi vs if ( cmd ) then echo OK; fi if [ "$(cmd)" == 'result' ]; then echo OK; fi vs if [ $(cmd) == 'result' ]; then echo OK; fi if [ -f PATH ]; then echo OK; fi vs if test -f PATH; then echo OK; fi

3. 2. Environment HISTSIZE="1000" HOME="/home/hackman" HOSTNAME="gamelon.azilian.net" LOGNAME="hackman" OLDPWD="/home/hackman" PATH="/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/lib/java/bin:/usr/lib/java/jre/bin:/opt/kde/bin" PWD="/tmp" SHELL="/bin/bash" SHLVL="3" TERM="xterm" USER="hackman" USERNAME="hackman"

4. 2. Environment SSH_AGENT_PID="2131" SSH_ASKPASS="/usr/libexec/openssh/gnome-ssh-askpass" SSH_AUTH_SOCK="/tmp/ssh-rHvhmB2112/agent.2112" SSH_CLIENT="87.118.135.1 58431 18765" SSH_CONNECTION="87.118.135.1 58431 72.18.172.13 18765" SSH_TTY="/dev/pts/0"

5. 3. Locality m=''; l=''; cat file | while read a; do if [ "$a" == 'XXX' ]; then m=$a; fi if [ "$a" == 'YYY' ]; then n=$a; fi done m & n are still ''

6. 4. Arrays l=(a b c) $ echo ${l[0]} a $ echo ${l[1]} ips=($(ip a l eth0|awk '/inet /{gsub(/.*/,"",$2);print $2}'))

7. 5. Commands ls cp mv rm echo cat cut wc seq tail head sort uniq date stat grep find sed awk