if 先来个实例: x=5; if [ $x = 5 ]; then echo 'x equals 5....中的条件语句, Test 是核心,if 和 case 熟悉语法即可。...循环 bash 中有 for 和 while 两种常见的循环体,我们应该都很熟悉。 for 直接上实例,批量修改文件名。...; done 语法其实很明朗: for variable [in
[student@studentvm1 testdir]$ 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 [ $X -eq 1 ] ; then echo "X equals 1" ; else echo "X does not equal 1" ; fi X does n...
#!/bin/bash #: Description : print formatted sales report ## Build a long string of equals signs divider=== divider=$divider$divider ## Format strings for printf header="\n %-10s %11s %8s %10s\n" format=" %-10s %11.2f %8d %10.2f\n" ## Width of divider totalwidth=44 ## Pri...
[student@studentvm1 testdir]$ MyVar="Random text" ; if [ -z "" ] ; then echo "MyVar is zero length." ; else echo "MyVar contains data" ; fi MyVar is zero length. 你也可以这样做: [student@studentvm1 testdir]$ MyVar="Random text" ; if [ -n "$MyVar" ] ; then echo "MyVar...
[student@studentvm1 testdir]$ MyVar="Random text" ; if [ -z "" ] ; then echo "MyVar is zero length." ; else echo "MyVar contains data" ; fi MyVar is zero length. 你也可以这样做: [student@studentvm1 testdir]$ MyVar="Random text" ; if [ -n "$MyVar" ] ; then echo "MyVar...
if 先来个实例: x=5; if [ $x = 5 ]; then echo 'x equals 5...[else commands] fi 这就是 if 的基本语法,其中紧接在 if 和 elif 后面的 commands 多数时候为 Test 。...中的条件语句, Test 是核心,if 和 case 熟悉语法即可。...循环 bash 中有 for 和 while 两种常见的循环体,我们应该...
我text可变负荷变化的text="$color${@: 2}${code}0m"这样整个线的参数除了要色色。 "tomazahlin只是添加到回声E,以上几个时代。仅为一个echo更改颜色的一个简单方法是定义这样的功能:12345678910111213141516171819 function coloredEcho(){ local exp=$1; local color=$2; if ! [[ $color =~ '^[0-9]$...
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 file: True if the file exists and the execute permission is set. In the table, "file" and "directory" can include directory paths, either relative or absolute. The equals sign "=" and the equality test-eqare not the same. The equals sign performs a character by character text compa...
$ type -t if keyword 上面例子中,bash是文件,if是关键词。 快捷键 Bash 提供很多快捷键,可以大大方便操作。下面是一些最常用的快捷键,完整的介绍参见《行操作》一章。 Ctrl + L:清除屏幕并将当前行移到页面顶部。 Ctrl + C:中止当前正在执行的命令。