file="/home/shiyanlou/test.sh" if [ -r $file ] then echo "The file is readable" else echo "The file is not readable" fi if [ -e $file ] then echo "File exists" else echo "File not exists" fi 结果 The file is readable File exists 思考 浮点运算,比如实现求圆的面积和周长。 exp...
如果第二次运行该脚本,将获得一个非零值,如下所示: [root@localhost ~]# sh myscript.sh 0 [root@localhost ~]# sh myscript.sh mkdir: cannot create directory ‘learning’: File exists 1 最佳实践 建议通过将set -x命令添加到shell脚本来启用调试模式,如下所示: [root@localhost ~]# cat test3.sh ...
ubuntu linux 에서 shell script 를 사용하다보면 파일의 유무를 확인해야 하는 경우가 자주 있습니다. 이럴 때 사용할 수 있는 방법은 조건문에서 특별한 옵션을 사용하는 것 입니다. 기...
When bash is invoked as an interactive login shell, or as a non-interactive shell with the –login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in...
Start by creating the script file:nano exists.shCopy and paste the following script:#!/bin/bash MyFile=cars.txt if [ -f "$MyFile" ]; then echo "$MyFile exists." else echo "$MyFile does not exist." fiRunning the script results in the following output:...
Here is our first bash shell script example: #!/bin/bash # declare STRING variable STRING="Hello World" #print variable on a screen echo $STRING Navigate to a directory where your hello_world.sh is located and make the file executable: ...
File exists 浮点运算,比如实现求圆的面积和周长。 expr只能用于整数计算,可以使用bc或者awk进行浮点数运算。 #!/bin/bash raduis=2.4 pi=3.14159 girth=$(echo "scale=4; 3.14 * 2 * $raduis" | bc) area=$(echo "scale=4; 3.14 * $raduis * $raduis" | bc) ...
# this is the first bash script echo"hello andy" 1. 2. 3. 4. (3)退出文件编辑,运行脚本:./或者source ,即可显示hello andy,这是一个最简单的demo啦。 note: (1)如果提示执行脚本没有权限-bash: ./: Permission denied则通过chmod...
File/usr/bin/boot.ini exists 请参阅之前的文章以了解各种bash if 语句类型。 Bash 示例 2. 比较数字 下面的脚本从用户那里读取两个整数,并检查这两个数字是否相等或大于或小于彼此。 $ cat numbers.sh #!/bin/bash echo"Please enter first number"read first ...
declare -rx SCRIPT=${0##*/} # SCRIPT is the name of this script declare -rx who=”/usr/bin/who” # the who command - man 1 who declare -rx TMP=”/tmp/temp.$$” # TMP is a temporary file # Sanity Checks if test ! -x “$who” ; then ...