= STRIN2 # Trueifstrings arenotequal#算术测试操作var1 -eq var2 # Trueifvar1 is equal to var2var1 -ne var2 # Trueifvar1notequal to var2var1 -lt var2 # Trueifvar1 is less than var2var1 -le var2 # Trueifvar1 is less thanorequal ...
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 the Regular Expression Operator =~?
[zexcon@fedora ~]$ ./learnToScript.sh numberTwelve variable is equal to 12 你所看到的是if语句的第一行,它在检查变量的值是否真的等于12。如果是的话,语句就会停止,并发出numberTwelve is equal to 12的回显,然后在fi之后继续执行你的脚本。如果变量大于12的话,就会执行elif语句,并在fi之后继续执行。当...
In this example the logicalORoperator combines two conditions and only one of them or both can be true for the condition to be overall true and the code to execute. We also demonstrate the-geoperator for greater or equal numeric comparison in the above example. The script is working as exp...
[ n1 -lt n2 ] (true if n1 less then n2, else false) String Comparisons: = - is equal to - if [ "$a" = "$b" ] == - is equal to - if [ "$a" == "$b" ] != - is not equal to - if [ "$a" != "$b" ] ...
In this example, we have two variables, ‘a’ and ‘b’. The script checks if ‘a’ is equal to ‘b’. If it’s not, it moves on to the ‘elif’ statement to check if ‘a’ is greater than ‘b’. If neither condition is met, it executes the ‘else’ statement, which in ...
!=: Not equal to -z: Empty string -n: Non-empty string 3. File and Directory Checks: -e: Exists -f: Regular file -d: Directory -r: Readable -w: Writable -x: Executable Example of using If Statement: Let’s illustrate the usage of if statements with a few examples: ...
{script-only-if-no-other-script} [input-file]...6Sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (afileor input from a pipeline). Whileinsome ways similar to an7editorwhichpermits scripted edits (such as ed),sedworks by making...
其次,Shell 是一个命令解释器,解释用户输入的命令。它支持变量、条件判断、循环操作等语法,所以用户可以用 Shell 命令写出各种小程序,又称为脚本(script)。这些脚本都通过 Shell 的解释执行,而不通过编译。 最后,Shell 是一个工具箱,提供了各种小工具,供用户方便地使用操作系统的功能。
Bash string comparison It is advisable always to check and compare if two strings are equal in a Bash script; this is quite important for different reasons. If two strings are equal in a Bash script, it implies that both strings have the same length and character sequence. The “if” stat...