Linux if command judgment condition summary, linuxif

Linux if command judgment condition summary, linuxif

Linux if command judgment condition Summary
Linux if command

Limit type of file attributes

-A: If the file exists

-B. If the file exists and the file is a regional Device File

-C: returns true if the file exists and is a character device file.

-D. If pathname exists and is a directory, true is returned.

-E: returns true if the file or directory specified by pathname exists.

-F returns true if the file exists and is a common file

-G returns true if the file or directory specified by pathname exists and the SGID bit is set.

-H returns true if the file exists and is a symbolic link file. This option is invalid in some old systems.

-K. If the file or directory specified by pathname exists and the "sticky" bit is set, the system returns true.

-R: returns true if the file or directory specified by pathname exists and is readable.

-S: returns true if the file size is greater than 0.

-T file descriptor if the file descriptor is enabled and linked to a terminal

-U returns true if a file or directory specified by pathname exists and SUID is set.

-W returns true if the file or directory specified by pathname exists and is executable. A directory must be executable for its content access.

-X if the file exists and the file has executable Properties

-O returns true if a file or directory specified by pathname exists and the user specified by the valid user ID of the current process is owned by it.

-G if the file exists and the file is owned by a valid group id

-L if the file exists and the file is a symbolic link file

-S if the file exists and the file is a Socket File

-N if the file exists and the file has been modified since the last read

File 1-nt file 2 if file 1 is newer than file 2, or file 1 exists, file 2 does not exist

File 1-ot file 2 if file 1 is older than file 2, or file 1 does not exist, file 2 exists

File 1-ef file 2 if file 1 and file 2 reference the same device and inode number

String-Based Conditional Criterion

-Z empty string (if the string length is 0)

-N non-empty string (if the string length is not 0)

If the length of a string is not 0

! = If the two strings are not equal

= If the two strings are equal

= If the two strings are equal

String 1 <string 2 if string 1 is smaller than string 2

String 1> string 2 if string 1 is greater than string 2

Conditional judgment of formula

-Eq equals

-Ne is not equal

-Gt greater

-Lt is less

-Le is less than or equal

-Ge is greater than or equal

Condition Determination of Bash options

-O set Option name if the option is enabled