The stat function

The file test operators of Section  provide useful ``yes/no'' information about files, but when you need to know, say, the exact date a file was accessed or modified, or the owner of the file, you will need something more powerful. Most information of this type could be produced by parsing the output of some operating system command, but a much more efficient way of getting this information is to use the stat function. You pass a valid filename to stat, and it returns an array with thirteen elements, as listed in Table .

Table: Elements returned by the stat function

Element
Number	Name	Meaning
0	dev	device number of filesystem
1	ino	inode number
2	mode	file mode (type and permissions)
3	nlink	number of (hard) links to the file
4	uid	numeric user ID of file's owner
5	gid	numeric group ID of file's owner
6	rdev	the device identifier (special files only)
7	size	total size of file, in bytes
8	atime	last access time in seconds since Jan 1, 1970
9	mtime	last modify time in seconds since Jan 1, 1970
10	ctime	inode change time in seconds since Jan 1, 1970
11	blksize	preferred block size for file system I/O
12	blocks	actual number of blocks allocated

Many times you will only need to extract a single value from the stat function. You can use the technique outlined in Section 4.3 to access only the pieces you want. Like the file test operators (Section ), the underscore can also be used to refer to the most recently queried file.