sh脚本中if条件

sh脚本中if条件

文件 含义

-r True if file exists and is readable

-w True if file exists and is writable

-x True if file exists and is executable

-f True if file exists and is a regular file

-d True if file exists and is a directory

-c True if file exists and is a character special file

-b True if file exists and is a block special file

-p True if file exists and is a named pipe (FIFO)

-u True if file exists and is a SETUID file

-g True if file exists and is a SETGID file

-k True if file exists and the sticky bit is set

-s True if file exists and has a size greater than zero

逻辑 含义

! Not

-a And

-o Or (has lower precedence that -a)

( ) Parentheses for grouping

数值 含义

-ne Not equal

-eq Equal

-gt Greater then

-ge Greater than or equal

-le Less than or equal

-lt Less than

其他 含义

-z str True if string length is zero

-n str True if string length is non-zero

str1 = str2 True if strings are identical. Note that this uses a single = symbol unlike
C’s equality operator.

str1 != str2 True if strings are not identical

str True if string is not the null string

1.if

“if” 表达式 如果条件为真则执行then后面的部分：

if ….; then

….

elif ….; then

….

else

….

fi