The easiest way to see how long a LINUX computer has been running is to issue the uptime command.

A typical output of the uptime command is:

 15:43:37 up 41 days, 16:10,  1 user,  load average: 0.11, 0.08, 0.08

The fields are:

1. Current time. This may be shown in a variety of formats (e.g. 3:43pm)
2. Length of time since last boot or IPL - the uptime. This may be shown in a variety of formats (e.g. up 7:24 for seven hours and twenty four minutes)
3. Number of terminal users
4. The load on the computer over the last 1, 5 and 15 minutes

Further information can be found by using the 'man uptime' command.

The current uptime of this machine is: