The integer operator file test character operation for bash in Linux is attached

 str if length is nonzero

Operator	Describe	Example
File comparison Operators
[-e file]	file exists, it is true	eg:[-e/etc/passwd]
[-d file]
[-f file]
[-l file]		eg:[-L  /etc/passwd ]
[-r file]	is readable, true	/etc/passwd   ]
[-w file]	is writable, true	/etc/passwd   ]
[-x file]	is executable, true	/etc/passwd   ]
[file1-nt File2]	file1 is newer than  file2 , then true	eg: [  -nt /ETC/PASSWD ]
[file1-ot File2]	file1 is older than  file2 , then true	eg: [/etc/passwd ]
string comparison operators
[-Z string] or [-Z variable]	True if str length is zero	Eg:[-Z "$STR"]
[-n ] or [-n variable]		eg:[-N "$tr"]
[ string 1=  str1 is the same as  str2 , then true	eg:["$str" = "This is a string"]
[ string 1!= 2]	true	str1 differs from  str2 7px;border:1px inset, "height=", "> eg:["$str"! = "this is a string "]
Arithmetic comparison operators
[Num1-eq num2]	Equals	eg:[1-eq $num]
[num1-ne num2]	is not equal to	eg:[2-ne $num]
[num1-lt num2]	less than
[num1-le num2]	less than or equal to
[num1-gt num2]	greater than
[Num1-ge num2]	Greater than or equal to	eg: [6-ge $num]

This article is from the "binary in the Network" blog, be sure to keep this source http://grivel.blog.51cto.com/979453/1851020

The integer operator file test character operation for bash in Linux is attached