chenxin@yunwei-01:~/1tmp$cat-A 1.sh#!/bin/bash$$date_tmp=`date +%s`$$cat <<- 'EOF' $ echo hello1$ echo hello2$ echo hello$ echo $date_tmp$EOF$$echo $date_tmp$chenxin@yunwei-01:~/1tmp$ ./1.sh echo hello1 echo hello2 echo hello echo $date_tmp1645672402 示例2: cat> e...
#!/bin/bash #: Description : print formatted sales report ## Build a long string of equals signs divider=== divider=$divider$divider ## Format strings for printf header="\n %-10s %11s %8s %10s\n" format=" %-10s %11.2f %8d %10.2f\n" ## Width of divider totalwidth=44 ## Pri...
[student@studentvm1 testdir]$ X=1 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X equals 1 [student@studentvm1 testdir]$ X=0 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X does n...
美元符号(Variable substitution[Dollar sign])。 1. 作为变量的前导符,用作变量替换,即引用一个变量的内容,比如:echo $PATH; 2. 在正则表达式中被定义为行末(End ofline)。 ${} 参数替换(Variable substitution)。 用于在字符串中表示变量。 $‘...’ ...
How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with...
If you follow those rules then you can avoid accidentally overwriting data stored in environmental variables. You can assign data to a variable using the equals sign (=). The data you store in a variable can either be a string or a number. Let’s create a variable now on the command li...
x=5;if[$x=5];then echo'x equals 5.';elseecho'x does not equal 5';fi # 输出: x equals5. 和我们熟悉的语言非常相似,不妨抽象一下: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ifcommands;then commands[elif commands;then
making them a good choice for basic array looping. ‘While’ and ‘until’ loops offer more control over the loop condition, which can be useful in more complex scenarios. However, they require you to manually manage a counter variable, which can lead to off-by-one errors if you’re not...
We’ll be checking whether 1 equals 2. If true, then the output will be “true”. Otherwise, the output will be “false”. $ test 1 -eq 2 && echo“true” || echo“false” Let’s break it down. test: The test command. 1: The first element for comparison. -eq: Comparison ...
[student@studentvm1 testdir]$ X=1 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X equals 1 [student@studentvm1 testdir]$ X=0 ; if [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X does n...