echo "It's me, $USER" 更改文件权限并运行脚本。你在上一章中已经学到了。 这是它为我生成的内容: Using global variable in Bahs script 你是否注意到它如何自动将我的名字添加到其中?这就是包含用户名的全局变量$USER的魔力。 你可能还注意到,我有时将"与echo一起使用,但其他时候则不使用。这是故意的。
验证“v=var echo $v”和“v=var; echo $v”命令的区别 基于前面说明,可知v=var echo $v和v=var; echo $v命令之间的区别在于,执行命令时的环境变量有所不同。 具体测试如下: $ v=varecho$v$ v=var;echo$vvar $ v=varenv| grep var v=var $ v=var;env| grep var 可以看到,v=var echo $v...
echo -e $variable 这样,将会按照换行符进行换行输出变量的值。 对于Bash/Shell脚本中插入换行符的应用场景,可以用于生成具有多行文本格式要求的配置文件、日志文件、邮件内容等。在这些场景下,使用换行符可以使文本更加清晰易读。 腾讯云相关产品和产品介绍链接地址: 腾讯云服务器(CVM):https://cloud.tencent.com/pro...
[ken@Dell-Desktop ~]$declare -r c1=3[ken@Dell-Desktop ~]$echo$c13[ken@Dell-Desktop ~]$c1=4-bash:c1:readonly variable 我们通过declare -r声明了一个只读(readonly)的变量c1,之后如果尝试修改它的话,就会提示失败。 其实这个declare的用法颇有一点复杂,这里稍微进一步介绍下 点击查看代码 [ken@Dell-D...
[root@www ~]# echo ${name:?tom} -bash: name: tom [root@www ~]# 子串削除: {varilable#*pattern}: 查找variable中自左而右第一次被pattern匹配到的串,将此串及向左的所有内容都删除{varilable##*pattern}: 查找variable中自左而右最后一次被pattern匹配到的串,将此串及向左的所有内容都删除 ...
echo 'Please enter your name.' #Here we are reading the standard input and assigning it to the variable name with the read command. read name #We are now going back to standard output, by using echo and printing your name to the command line. ...
#variable with a string stringItem="Hello" #This will match since it is looking for an exact match with $stringItem if [[ $stringItem = "Hello" ]] then echo "The string is an exact match." else echo "The strings do not match exactly." ...
testexits with the status determined by EXPRESSION. Placing the EXPRESSION between square brackets ([and]) is the same as testing the EXPRESSION withtest. To see the exit status at the command prompt, echo the value “$?” A value of 0 means the expression evaluated as true...
math_lines=$(catmath.sh|wc-l)echo$math_lines ## 7 Variable names with a dollar sign can also be used inside other strings in order to insert the value of the variable into the string: echo"I went to school in$the_empire_state." ...
read variable_name 其中,variable_name是你自定义的变量名,用于保存用户输入的值。读取用户输入后,可以通过该变量名来获取输入的内容。 以下是获取用户输入的完整示例代码: 代码语言:txt 复制 #!/bin/bash echo "Please enter your name: " read name echo "Hello, $name! How are you?" 在上述代码中,用户...