demo@1[demo]$ pr aux
pr: aux: No such file or directory
demo@1[demo]$ ps aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.1  0.0   1564   532 ?        S    17:51   0:01 init [5] 
root         2  0.0  0.0      0     0 ?        SN   17:51   0:00 [ksoftirqd/0]
root         3  0.0  0.0      0     0 ?        S    17:51   0:00 [watchdog/0]
root         4  0.0  0.0      0     0 ?        S<   17:51   0:00 [events/0]
root         5  0.0  0.0      0     0 ?        S<   17:51   0:00 [khelper]
root         6  0.0  0.0      0     0 ?        S<   17:51   0:00 [kthread]
root         8  0.0  0.0      0     0 ?        S<   17:51   0:00 [kblockd/0]
root         9  0.0  0.0      0     0 ?        S<   17:51   0:00 [kacpid]
root       109  0.0  0.0      0     0 ?        S<   17:51   0:00 [khubd]
root       162  0.0  0.0      0     0 ?        S    17:51   0:00 [pdflush]
root       163  0.0  0.0      0     0 ?        S    17:51   0:00 [pdflush]
root       165  0.0  0.0      0     0 ?        S<   17:51   0:00 [aio/0]
root       164  0.0  0.0      0     0 ?        S    17:51   0:00 [kswapd0]
root       756  0.0  0.0      0     0 ?        S<   17:51   0:00 [kseriod]
root       878  0.0  0.0      0     0 ?        S<   17:51   0:00 [ata/0]
root       879  0.0  0.0      0     0 ?        S<   17:51   0:00 [ata_hotplug/0]
root       888  0.0  0.0      0     0 ?        S<   17:51   0:00 [scsi_eh_0]
root       889  0.0  0.0      0     0 ?        S<   17:51   0:00 [scsi_eh_1]
root       908  0.0  0.0      0     0 ?        S    17:51   0:00 [khpsbpkt]
root       980  0.0  0.0      0     0 ?        S<   17:51   0:00 [loop0]