Thepatternwillmatchif itmatchesanypartofthe string. Anchor thepatternusingthe ‘^’and‘$’ regular expression operatorstoforce ittomatchthe entire string. Thearrayvariable BASH_REMATCH records which partsofthe string matched the pattern. The elementofBASH_REMATCHwithindex0containstheportionofthe string...
else echo "Strings are not equal." fi 2. 使用 tr 命令去除所有空白字符 代码语言:txt 复制 string1=$(echo "your_string" | tr -d '[:space:]') string2=$(echo "your_string" | tr -d '[:space:]') if [ "$string1" == "$string2" ]; then echo "Strings are equal." else echo...
/bin/sha="abc"b="efg"if[ $a =$b ]thenecho"$a = $b : a is equal to b"elseecho"$a = $b: a is not equal to b"fiif[ $a !=$b ]thenecho"$a != $b : a is not equal to b"elseecho"$a != $b: a is equal to b"fiif[ -z $a ]thenecho"-z $a : string length...
if [ "$a" -gt "$b" ]; then echo "$a is greater than $b" elif [ "$a" -eq "$b" ]; then echo "$a is equal to $b" else echo "$a is less than $b" fi 循环:包括 for 循环和 while 循环。 # for 循环 for i in {1..5}; do echo "Number: $i" done # while 循环...
[zexcon@fedora ~]$ ./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...
- Test if a given variable is equal/not equal to the specified string: [[ $variable ==|!= "string" ]] - Test if a given string conforms the specified glob/regex: [[ $variable ==|=~ pattern ]] - Test if a given variable is [eq]ual/[n]ot [e]qual/[g]reater [t]han/[l]...
The EXPRESSION is false. -n STRING The length of STRING is greater than zero. -z STRING The lengh of STRING is zero (ie it is empty). STRING1 = STRING2 STRING1 is equal to STRING2 STRING1 != STRING2 STRING1 is not equal to STRING2 INTEGER1 -eq INTEGER2 INTEGER1 is numerically ...
How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with the Regular Expression Operator =~?
if [ -z "$input_str" ]; then echo "The string is empty" else echo "The string is not empty" fi Output: The string is empty Explanation: In the exercise above, The variable 'input_str' is defined as an empty string. An if statement checks if the length of '$input_str' is zero...
the variable X is not the empty string 为何?这是因为shell将$X展开为空字符串,表达式[-n]返回真值(因为改表达式没有提供参数)。再看这个脚本: #!/bin/bash X="" if [ -n "$X" ]; then # -n 用来检查变量是否非空 echo "the variable X is not the empty string" ...