/bin/bash filename=”example.txt” if [ -e $filename ] then echo “$filename exists.” else echo “$filename does not exist.” fi “` 在这个例子中,使用了-e选项来判断文件是否存在。如果文件存在,则输出”$filename exists.”,否则输出”$filename does not exist.”。 ## 判断数字的大小 ...
在Linux命令行中,我们可以使用`-e`选项判断文件是否存在。以下代码判断文件`/etc/passwd`是否存在: “`bash #!/bin/bash file=”/etc/passwd” if [ -e $file ] then echo “$file exists.” else echo “$file does not exist.” fi “` 五、多条件判断 在实际编程中,我们可能需要同时判断多个条件,...
[file1 –nt file2]如果file1 has been changed more recently than file2或者file1 exists and file2 does not则为真 [file1 –ot file2]如果file1比file2要老,或者file2存在且file1不存在则为真 [file1 –ef file2]如果file1和file2指向相同的设备和节点号则为真 [-o optionname]如果shell选项“...
然而,尽管存在这些限制,Linux在各个领域都有广泛的应用。首先,对于服务器和超级计算机来说,由于Linux的稳定性和可靠性,成为首选操作系统。许多云服务提供商和大型科技公司,如Google和Amazon,都基于Linux构建了自己的服务和产品。其次,在移动设备领域,Android操作系统也是基于Linux开发的,如今已经成为全球使用最广泛的移动...
[ -N FILE ] 如果 FILE 存在 and has been mod如果ied since it was last read则为真。[ -S FILE ] 如果 FILE 存在且是⼀个套接字则为真。[ FILE1 -nt FILE2 ] 如果 FILE1 has been changed more recently than FILE2, or 如果 FILE1 exists and FILE2 does not则为真。[ FILE1 -ot FILE...
[22:21:24 root@libin3 libin]# vim shell20 #!/bin/bash # echo this is if status if date then echo "I'm is libin" fi [22:22:59 root@libin3 libin]# chmod u+x shell20 [22:23:06 root@libin3 libin]# ./shell20 2022年08月11日 星期四22:23:11 CST ...
-L file exists and is a symbolic link. -n string length is not zero. -o Named option is set on. -O file exists and is owned by the user ID of this process. -p file exists and is a first in, first out (FIFO) special file or ...
if [ -f /path/to/file ]; then echo "File exists." fi if-else语句 如果需要在满足条件时执行一组命令,在不满足条件时执行另一组命令,可以使用if-else结构: bash 复制代码 if [ 条件 ]; then # 如果条件为真,执行这里的命令 else # 如果条件为假,执行这里的命令 fi ...
Check If File Exists In order to check if a file exists in Bash, you have to use the “-f” option (for file) and specify the file that you want to check. if [[ -f <file> ]] then echo "<file> exists on your filesystem." ...
In Bash you can use the test command to check whether a file exist and determine the type of the file.