Unix as a Second Language

Long listings for the ps command

Ever jump onto a Unix system to help resolve a critical problem and find that the information you most want to see in your ps output has run off the right edge of your terminal window? Who hasn't? Fortunately, the various flavors of Unix have command options to allow you to view the text that is normally truncated.

On Linux systems, for example, there is an "l" (long) option that will turn output such as this:


# ps -ef | egrep "apache|CMD"
UID PID PPID C STIME TTY TIME CMD
root 13379 1 0 Jul31 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 21193 13379 0 Aug01 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 7674 13379 0 Aug04 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 7767 13379 0 Aug04 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 7768 13379 0 Aug04 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 7772 13379 0 Aug04 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 7773 13379 0 Aug04 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 12341 13379 0 Aug06 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 13810 13379 0 Aug06 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 13811 13379 0 Aug06 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s
daemon 13812 13379 0 Aug06 ? 00:00:00 /var/local/ap
ache/bin/httpd -k s


into output that looks like this:


# ps -elf | egrep "apache|CMD"
F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME
TTY TIME CMD
140 S root 13379 1 0 75 0 - 1234 schedu Jul31
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 21193 13379 0 75 0 - 1289 schedu Aug01
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 7674 13379 0 75 0 - 1289 schedu Aug04
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 7767 13379 0 75 0 - 1289 schedu Aug04
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 7768 13379 0 75 0 - 1289 schedu Aug04
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 7772 13379 0 75 0 - 1289 schedu Aug04
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 7773 13379 0 75 0 - 1289 schedu Aug04
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 12341 13379 0 75 0 - 1289 schedu Aug06
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 13810 13379 0 75 0 - 1286 schedu Aug06
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 13811 13379 0 75 0 - 1286 schedu Aug06
? 00:00:00 /var/local/apache/bin/httpd -k start
140 S daemon 13812 13379 0 75 0 - 1286 schedu Aug06
? 00:00:00 /var/local/apache/bin/httpd -k start


You not only get the complete command line, but several extra fields are included. For example, WCHAN, which indicates the event on which the process is waiting, is shown in the 11th column in this output.

Solaris systems, on which I spend most of the e-time, also provide the "l" (long) option, though they generally wrap the ps output onto the following line rather than truncate ps output.

Mac OS X systems, which still use the "aux" version of the ps command, offer a "w" (wide) option which provides 132 columns in ps output instead of the default 80.

The order in which the arguments to ps arguments are presented is arbitrary, though I have always seen "ef" and "aux" as the standards, maybe because the letters in the argument list are in alphabetical order. I prefer "elf" to "efl" since its an easy-to-remember and friendly word and "uwax" to "auwx" for a similar reason, but you can adopt whatever argument order appeals to you.