if 先来个实例: x=5; if [ $x = 5 ]; then echo 'x equals 5....中的条件语句, Test 是核心,if 和 case 熟悉语法即可。...循环 bash 中有 for 和 while 两种常见的循环体,我们应该都很熟悉。 for 直接上实例,批量修改文件名。...; done 语法其实很明朗: for variable [in
then the variable is “Not Set.” Similarly, when a variable is defined and has a value, then it is “Set.” Thus, declared variable but no value equals to “Not Set,” and declared variable with value equals to “Set.”
#!/bin/bash #: Description : print formatted sales report ## Build a long string of equals signs divider=== divider=$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...
Check if numbers are equal The-eqoperator checks if Integer1 equals Integer2. If integer1 equals integer2, then it returns 0, else it returns 1: [ 10 -eq 20 ] && echo $? || echo $? Check if the numbers are not equal Case 2. The-neoperator checks if integer1 is not equal to ...
How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with...
not equals:-ne is empty:-z if[[1-eq1]];if[[-z$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 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...
-x file: True if the file exists and the execute permission is set. ✕Remove Ads In the table, "file" and "directory" can include directory paths, either relative or absolute. The equals sign "=" and the equality test-eqare not the same. The equals sign performs a character by char...
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...
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 ...