a) echo "Found the -a option" ;; b) echo "Found the -b option, with value $OPTARG";; c) echo "Found the -c option" ;; *) echo "Unknown option: $opt";; esac done $ $ ./test19.sh -ab test1 -c Found the -a option Found the -b option, with value test1 Found the -c...
"=value".# "VARIABLE= value"# ^#% Script tries to run "value" command with#+ the environmental variable "VARIABLE" set to "".#---## 变量引用echohello# hello# Not a variable reference, just the string "hello" ...echo$hello# 375# ^ This *is* a variable reference.echo${hello}# ...
$ echo "var1=$var1; var2=$var2; var3=$var3" var1=101; var2=202; var3=303 If we replace the hard-coded string with acommand substitution, we can set multiple variables using a command’s output. Let’s test with the seven variables and thedatecommand scenario: $ read -r WEEK ...
$ echo $yourname tina 2.2-p 参数,允许在 read 命令行中直接指定一个提示 $ read -p "input your name:" username input your name:tina $ echo $username tina 输入多个变量 1 #!/bin/bash 2 # entering multiple variables 3 4 read -p "Enter your name:" first last 5 echo "Checking data fo...
When writing a Bash script, the script gives you a few variables for free. Let’s create a new file calledvars.shwith the following code: #!/usr/bin/env bash # File: vars.sh echo "Script arguments: $@" echo "First arg: $1. Second arg: $2." ...
echo $OUTPUT *为什么OUTPUT带不带双引号,区别这么大呢? Jonathan Leffler解释如下: The difference is that: (1) the double-quoted version of the variable (echo "$VARIABLE") preserves internal spacing of the value exactly as it is represented in the variable — newlines, tabs, multiple blanks and...
echo -n >file printf '' >file 1. 2. 3. 4. 5. 6. 7. 提取两个标记之间的线条 示例功能: extract() { # Usage: extract file "opening marker" "closing marker" while IFS=$'\n' read -r line; do [[ $extract && $line != "$3" ]] && ...
stat命令提供文件系统中文件状态的完整摘要,执行该命令的结果可以显示目标文件的所有信息,甚至包括存储文件的设备的主设备号和次级设备号。执行stat --h查看该命令的参数: 根据上述,执行stat实例的结果如下所示: 2.查看文件类型(file) file命令是一个方便的实用程序。它可以查看文件内部并确定文件类型。使用file --h...
[root@jfht ~]#echo "hello world\ >yes" hello worldyes [root@jfht ~]# 在双引号中,感叹号(!)的含义根据使用的场合有所不同,在命令行环境,它将被解释为一个历史命令,而在脚本中,则不会有特殊含义。 Advanced Bash-Scripting Guide: 5.1. Quoting Variables 写道 ...
auto-export of variables in initial environment command search finds functions before builtins bash return builtin will exit a file sourced with `.' builtins: cd -/-L/-P, exec -l/-c/-a, echo -e/-E, hash -d/-l/-p/-t. export -n/-f/-p/name=value, pwd -L/-P, read -e/...