A quick question from my mail bag:

How do I display or get the date when a file was last time accessed?

The best and simplest way is to use stat command. It displays file or file system status such as:

=> File size

=> File type

=> Inode number

=> UID/GID

=> File access , modify and creation time etc.

stat command example

$ stat /etc/passwd
Output

  File: `/etc/passwd'
  Size: 2453            Blocks: 8          IO Block: 4096   regular file
Device: 806h/2054d      Inode: 25298826    Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2007-08-06 04:45:18.000000000 -0500
Modify: 2007-07-17 16:25:12.000000000 -0500
Change: 2007-07-17 16:25:12.000000000 -0500

Display file system status

You can display file system status instead of file status. For example, display status for / file system:
$ stat -f /
Output:

  File: "/"
    ID: 0        Namelen: 255     Type: ext2/ext3
Block size: 4096       Fundamental block size: 4096
Blocks: Total: 32161831   Free: 30458361   Available: 28798245
Inodes: Total: 33226752   Free: 33135357

stat command and shell scripts

You can use stat in a shell script. It supports -c option. By default it shows all information about file. Use -c option to specify FORMAT instead of the default. For example store access time in a shell variable:

ATIME=$(stat -c "%x" /etc/passwd)
echo $ATIME

See the stat command man page for full details for the valid format sequences for files:
man stat