Operator Description<br /><br /> ! EXPRESSION The EXPRESSION is false.<br /><br /> -n STRING The length of STRING is greater than zero.<br /><br /> -z STRING The lengh of STRING is zero (ie it is empty).<br /><br /> STRING1 = STRING2 STRING1 is equal to STRING2<br /><br /> STRING1 != STRING2 STRING1 is not equal to STRING2<br /><br /> INTEGER1 -eq INTEGER2 INTEGER1 is numerically equal to INTEGER2<br /><br /> INTEGER1 -gt INTEGER2 INTEGER1 is numerically greater than INTEGER2<br /><br /> INTEGER1 -lt INTEGER2 INTEGER1 is numerically less than INTEGER2<br /><br /> -d FILE FILE exists and is a directory.<br /><br /> -e FILE FILE exists.<br /><br /> -r FILE FILE exists and the read permission is granted.<br /><br /> -s FILE FILE exists and it’s size is greater than zero (ie. it is not empty).<br /><br /> -w FILE FILE exists and the write permission is granted.<br /><br /> -x FILE FILE exists and the execute permission is granted.<br /><br />

and – &&<br /><br /> or – ||</p><br /> <p># and example<br /><br /> if [ -r $1 ] && [ -s $1 ]<br /><br /> then<br /><br /> echo This file is useful.<br /><br /> fi</p><br /> <p># or example<br /><br /> if [ $USER == ‘bob’ ] || [ $USER == ‘andy’ ]<br /><br /> then<br /><br /> ls -alh<br /><br /> else<br /><br /> ls<br /><br /> fi

#!/bin/bash</p><br /> <p>foo=”qux”<br /><br /> bar=”qux”</p><br /> <p>if [ “$foo” = “$bar” ]; then<br /><br /> echo “The strings are equal.”<br /><br /> else<br /><br /> echo “The strings aren’t equal.”<br /><br /> fi

if [[ $? -ne 0 ]]; then # -ne: not equal</p><br /> <p>if ! [[ $? -eq 0 ]]; then # -eq: equal</p><br /> <p>if [[ ! $? -eq 0 ]]; then<br /><br />

if [ “$animal” == “penguin” ]; then<br /><br /> echo “Hmmmmmm fish… Tux happy!”<br /><br /> elif [ “$animal” == “dolphin” ]; then<br /><br /> echo “Pweetpeettreetppeterdepweet!”<br /><br /> else<br /><br /> echo “*prrrrrrrt*”<br /><br /> fi</p><br /> <p>if TEST-COMMANDS; then<br /><br /> CONSEQUENT-COMMANDS;<br /><br /> elif MORE-TEST-COMMANDS; then<br /><br /> MORE-CONSEQUENT-COMMANDS;<br /><br /> else<br /><br /> ALTERNATE-CONSEQUENT-COMMANDS;<br /><br /> fi

if [ “$result” == “1” ]<br /><br /> then<br /><br /> echo “test” >> /home/samurai/test.txt<br /><br /> fi</p><br /> <p> if [[ “$result” -eq “1” ]]<br /><br /> then<br /><br /> echo “test” >> /home/samurai/test.txt<br /><br /> fi<br /><br />

# Basic syntax<br /><br /> if [[ condition_1 ]]; then<br /><br /> echo “Code to execute if condition_1 is true”<br /><br /> elif [[ condition_2 ]]; then<br /><br /> echo “Code to execute if condition_1 is false and condition_2 is true”<br /><br /> else<br /><br /> echo “Code to execute if condition_1 and condition_2 are false”<br /><br /> fi</p><br /> <p># Note, the syntax for the one-line equivalent is:<br /><br /> if [[ condition_1 ]]; then echo “Code to execute if condition_1 is true”; elif [[ condition_2 ]]; then echo “Code to execute if condition_1 is false and condition_2 is true”; else echo “Code to execute if condition_1 and condition_2 are false”; fi</p><br /> <p># Note to self, see this link for more on bash operators and [ ] vs [[ ]]:<br /><br /> # https://tldp.org/LDP/abs/html/comparison-ops.html

if [ “${STATUS}” != 200 ] && [ “${STRING}” != “${VALUE}” ]; then

nome=tiago<br /><br /> ## with SPACE between variable and comparation<br /><br /> if [ $nome == ‘tiago’ ] ;<br /><br /> then<br /><br /> echo “hello Tiago”<br /><br /> fi

if [[ some condition ]]; then<br /><br /> do_this<br /><br /> elif [[ another condition ]]; then<br /><br /> do_that_a<br /><br /> elif [[ yet another condition]]; then<br /><br /> do_that_b<br /><br /> else<br /><br /> do_that_default_thing<br /><br /> fi<br /><br />