/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 ...
-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 named pipe. -r file exists and is readable by ...
[ -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...
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 “$file does not exist.” fi “` 五、多条件判断 在实际编程中,我们可能需要同时判断多个条件,...
if exists linux 如果存在Linux Linux作为一种开源操作系统,已经在计算机领域得到了广泛的应用。但是,在选择操作系统时,很多人可能会对Linux存在一些疑问,比如“如果存在Linux,为什么还有人选择其他操作系统?”本文将探讨这个问题,并简要介绍Linux的特点及其在不同领域的应用。
if [ -f /path/to/file ]; then echo "File exists." fi if-else语句 如果需要在满足条件时执行一组命令,在不满足条件时执行另一组命令,可以使用if-else结构: bash 复制代码 if [ 条件 ]; then # 如果条件为真,执行这里的命令 else # 如果条件为假,执行这里的命令 fi ...
-eFILE- True if the FILE exists and is a file, regardless of type (node, directory, socket, etc.). -fFILE- True if the FILE exists and is a regular file (not a directory or device). -GFILE- True if the FILE exists and has the same group as the user running the command. ...
[ -s FILE ] 如果 FILE 存在且大小不为0则为真。 [ -t FD ] 如果文件描述符 FD 打开且指向一个终端则为真。 [ -u FILE ] 如果 FILE 存在且设置了SUID (set user ID)则为真。 [ -w FILE ] 如果 FILE 存在且是可写的则返回为真。(一个目录为了它的内容被访问必然是可执行的) ...
Another use case for "if -ne" is in file operations, such as checking if a file exists before performing any actions on it. Let's say we have a script that needs to process a specific file only if it exists. By utilizing "if -ne," the script can verify the file's existence and...
echo"File exists" fi (30)脚本定义while循环语句 #!/bin/bash if[ -f /home/wenmin/datas ] then echo"File exists" fi [root@rich datas]# cat while.sh #!/bin/bash s=0 i=1 while[$i-le 100 ] do s=$[$s+$i] i=$[$i+ 1] ...