Bash scripting tricks
Bash tricks Check bash version in script if ((BASH_VERSINFO[0] < 4)) then echo “Sorry, you need at least bash-4.0 to run this script.” exit 1 fi Reading columns from a file in bash array table_collection=( $(cut -d $’\t’ -f1...
Tagged: linux
AWK Syntax
AWK syntax: awk [-Fs] “program” [file1 file2…] # commands come from DOS cmdline awk ‘program{print “foo”}’ file1 # single quotes around double quotes # NB: Don’t use single quotes alone if the embedded info will contain the # vertical bar...
Chart of similar operations with sed and awk
Chart of similar operations with sed and awk ——————————————– string ====== sed “s/from/to/” awk ‘{sub(“from”,”to”); print}’ sed “s/from/to/g” awk ‘{gsub(“from”,”to”); print}’ sed “s/from/to/3” awk ‘{$0=gensub(“from”,”to”,3); print}’ regex ===== sed “s/reg.*$/_&_/” awk ‘{sub(/reg.*$/, “_&_”); print}’ sed “s/reg[ex]/YY/g” awk ‘{gsub(/reg[ex]/, “YY”); print}’...
awk one liners
HANDY ONE-LINE SCRIPTS FOR AWK 30 April 2008 Compiled by Eric Pement – eric [at] pement.org version 0.27 Latest version of this file (in English) is usually at: http://www.pement.org/awk/awk1line.txt This file will also be available in other languages: Chinese -...
awk one liners (old)
————————————————————————- HANDY ONE-LINERS FOR AWK (Unix stream editor) Apr. 17, 2001 compiled by Eric Pement <[email protected]> version 0.1 Latest version of this file is usually at: http://www.student.northpark.edu/pemente/awk/awk1line.txt USAGE: Unix: awk ‘/pattern/ {print “$1”}’ # standard Unix shells DOS/Win: awk ‘/pattern/...
Setting up password-less ssh across all nodes in a cluster
Pre-requisites User account for which passwordless ssh will be setup, should be present on all nodes Password of the account should be same across all nodes pdsh and ssh-copy-id commands should be available Prepare 2 files file_of_hosts.txt – containing all...
top command on linux
Usage Basic $ top View by process name # top -p $(pgrep -d’,’ <process name>) # sample below, top -p $(pgrep -d’,’ http) View by user top -u <user name> Sort by mem # Inside top Shift+m View command...
AWK quick reference
Tips Original article Tips awk regex awk ‘/[0-9]+ /{print}’ file.txt not beginning with an expression awk ‘!/^anexpression/{print}’ file.txt containing x and not containing y awk ‘/x/ && !/y/’ file.txt Mixing single and double quotes $ awk ‘BEGIN...
VI quick reference
Introduction vi pronounced as ” vee eye ” is a unix editor available on almost all the unix operating systems , solaris , bsd ,aix , hpux etc. This document is a quick reference to vi editor and will be...
Crontab quick reference
Crontab generators http://www.crontab-generator.org/ http://www.openjs.com/scripts/jslibrary/demos/crontab.php http://corntab.com/ Source: http://www.adminschoice.com/crontab-quick-reference Setting up cron jobs in Unix and Solaris cron is a unix, solaris utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon. These...
