Condition judgment

Test options

effect

-b file

Determine if the file exists , And whether it is a block device file （ It's a block of device files that are true ）

-c file

Determine if the file exists , And whether it is a character device file （ Is the character device file true ）

-d file

Determine if the file exists , And whether it is a directory file

-e file

Determine if the file exists

-f file

Determine if the file exists , And whether it's a normal document

-L file

Determine if the file exists , And whether it is a symbolic link file

-p file

Determine if the file exists , And whether it's a pipeline file

-s file

Determine if the file exists , And whether it is non empty

-S file

Determine if the file exists , And is it a socket file

Test options

effect

-r file

Determine if the file exists , And whether the file has read permission

-w file

Determine if the file exists , And whether the file has write permission

-x file

Determine if the file exists , And whether the file has execution permission

-u file

Determine if the file exists , And whether the file owns SUID jurisdiction

-g file

Determine if the file exists , And whether the file owns SGID jurisdiction

-k file

Determine if the file exists , And whether the file owns SBit jurisdiction

Test options

effect

file 1 -nt file 2

Judge documents 1 Whether the modification time of the file is longer than 2 The new （ New is true ）

file 1 -ot file 2

Judge documents 1 Whether the modification of is better than that of the file 2 The old （ Old is true ）

file 1 -ef file 2

Judge documents 1 Whether or not to file 2 Of Inode No , It can be understood as whether two files are the same file . This judgment is a good way to judge hard links .

Test options

effect

Integers 1 -eq Integers 2

Judgement integer 1 Whether or not and integers 2 equal （ Equality is true ）

Integers 1 -ne Integers 2

Judgement integer 1 Whether or not and integers 2 It's not equal （ Inequality is true ）

Integers 1 -gt Integers 2

Judgement integer 1 Is it greater than an integer 2（ Greater than is true ）

Integers 1 -lt Integers 2

Judgement integer 1 Is it less than an integer 2（ Less than is true ）

Integers 1 -ge Integers 2

Judgement integer 1 Whether it is greater than or equal to an integer 2（ Greater than or equal to true ）

Integers 1 -le Integers 2

Judgement integer 1 Is it less than or equal to an integer 2（ Less than or equal to true ）

Test options

effect

-z character string

Determines if the string is empty （ Empty is true ）

-n character string

Determine whether the string is non empty （ Not empty is true ）

character string 1 == character string 2

Judgment string 1 And 2 Whether it is equal or not （ Equality is true ）

character string 1 != character string 2

Judgment string 1 And 2 Is it unequal （ Inequality is true ）

Test options

effect

Judge 1 -a Judge 2

Logic and , Judge 1 And judgment 2 All set up , The result returns true

Judge 1 -o Judge 2

Logic or , Judge 1 And judgment 2 There is a foundation , The result returns true

！ Judge

Logic is not , Reverse the original judgment