Check if the string is empty The-zflag checks whether the string length is zero. If the string length is zero, it returns true, else it returns false: $ [ -z "sam" ] && echo "True" || echo "False" Check if stri
-z is the second supported bash string comparison operator used to check if a string is empty or not. The -z operator functions similarly like -n operator. Below is an example: Most importantly, you should add spaces around the square brackets. If there are no spaces, bash will complain ...
How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with...
#!/bin/bash #: Description : print formatted sales report ## Build a long string of equals signs divider=== divider=$divider$divider ## Format strings for printf header="\n %-10s %11s %8s %10s\n" format=" %-10s %11.2f %8d %10.2f\n" ## Width of divider totalwidth=44 ## Pri...
not equals:-ne is empty:-z if[[1-eq1]];if[[-z$USER]]; Elif if[[-z$USER]];thenecho"user is empty"elif[[1-eq1]];thenecho"1==1"elseecho"false"fi Ternary [[$USER='username']]&&echo"yes"||echo"no" Exp: check_status(){## Get HTTP status codelocalstatus=$(curl-ILs$1|...
if [[ $USER = 'username' ]]; then echo "true" else echo "false" fi 1. 2. 3. 4. 5. not equal:!= numeric equality:-eq not equals:-ne is empty:-z if [[ 1 -eq 1 ]]; if [[ -z $USER ]]; 1. 2. 3. Elif if [[ -z $USER ]]; then ...
Given the recent swath of articles covering the fundamental aspects of Bash (listed at the end of this article), it’s inevitable that one of your ne...
test "this string" = "that string" test 1 = 001 test 1 -eq 001 In each case, we usetheechocommandto print the return code of the last command. Zero means true, one means false. Using the equals sign "=" gives us a false response comparing 1 to 001. That's correct, because the...
If you follow those rules then you can avoid accidentally overwriting data stored in environmental variables. You can assign data to a variable using the equals sign (=). The data you store in a variable can either be a string or a number. Let’s create a variable now on the command li...
If the statement is true, the code is executed. if statements in bash script use square brackets for the logical condition and also have support for else and elif (else if) branches. Bash supports standard programming language conditional operators such as equals (==), not equals (!=), ...