Variable.sh代码如下: #!/bin/bash fruit=apple count=5 echo "we have $count $fruit(s)" [cairui@cai shell]$ sh variable.sh we have 5 apple(s) Export命令就是用来设置环境变量: [cairui@cai shell]$ echo $PATH /application/mysql/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/...
variable_int=100 # 访问变量, 在变量前添加 $ 符号, 该符号的目的是告诉 Shell 访问变量的值而非变量名本身 # echo 是 Linux 终端命令, 主要将文本, 变量, 和特殊字符输出到标准输出 ( 通常是终端屏幕 ) echo $variable_str echo $variable_int 实际上访问变量时需使用 "" 防止通配符扩展和单词拆分。① ...
首先,Shell 是一个程序,提供一个与用户对话的环境。这个环境只有一个命令提示符,让用户从键盘输入命令,所以又称为命令行环境(commandline,简写为 CLI)。Shell 接收到用户输入的命令,将命令送入操作系统执行,并将结果返回给用户。本书中,除非特别指明,Shell 指的就是命令行环境。 其次,Shell 是一个命令解释器,解释...
Occasionally you might want to run a command like you would on the command line and store the result of that command in a variable. We can do this by wrapping the command in a dollar sign and parentheses ($( )) around a command. This syntax is calledcommand substitution. The command is...
参考:https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash 6、换算秒为分钟、小时 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bash a=60100 swap_seconds () { SEC=$1 (( SEC < 60 )) && echo -e "持续时间: $SEC秒\c" (( SEC >= 60...
command [args] <<<["]$word["];$word会展开并作为command的stdin。 <<< 就是将后面的内容作为前面命令的标准输入 grep a <<< "$VARIABLE" 意思就是在VARIABLE这个变量值里查找字符a 示例 chenxin@yunwei-01:~$ aaa='this is bbb'chenxin@yunwei-01:~$ grep bbb <<<$aaathisis bbbchenxin@yunwei-01...
This command runs the script, prompting you to enter a decimal number. The script then converts the inputted decimal number to its octal equivalent and prints the result. Use Case #8: Print Date Variable To create a script that utilizesprintftodisplay the current date and time, follow these...
Use "echo" command to output the value of 'product'. Test the "multiply()" function by calling it with two numbers and storing the result in a variable 'result'. Finally, we print the result. 4. Division Function: Write a Bash script that creates a function called divide that takes tw...
The exit status of the wait command is printed. $? is an internal Bash variable that holds the exit status of the last command executed. If you run the script, it will print something like this: PID:36353Exit status:0 Here’s an example using the -n option: ...
Bash behaves as if the following command were exe- cuted: if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi but the value of the PATH variable is not used to search for the file name. If bash is invoked with the name sh, it tries to mimic the startup behavior of historical ...