File Timestamps [classic]

Each file has three timestamps associated with it (stored as the number of seconds since the Epoch, Jan 1, 1970). The three timestamps are:

• Access time (atime) - the last time the file was read
• Modify time (mtime) - the last time the file contents were changed
• Change time (ctime) - the last time the file permissions were changed

In a long directory listing, the timestamp shown is the Modify time (mtime). To see all timestamps and a lot of other useful information, use the stat program with the verbose option (-x):
stat -x filename

Here is sample output from stat:
keithw$ stat -x "Mona Lisa Overdrive.mp3"
File: "Mona Lisa Overdrive.mp3"
Size: 6853358 FileType: Regular File
Mode: (0644/-rw-r--r--) Uid: (501/ keithw) Gid: (501/ keithw)
Device: 14,9 Inode: 10208 Links: 1
Access: Fri May 25 11:46:30 2007
Modify: Fri Dec 8 16:38:54 2006
Change: Fri Dec 8 16:38:54 2006