[SOLVED] sorting ps output

fanoflq · 01-24-2017, 03:30 PM

ps output sort on PID in ascending order:

Code:

$ ps -eo user,pid,pri,ni,cmd --sort=pid
USER       PID PRI  NI CMD
root         1  19   0 /sbin/init splash
root         2  19   0 [kthreadd]
root         3  19   0 [ksoftirqd/0]
root         5  39 -20 [kworker/0:0H]
root         7  19   0 [rcu_sched]
root         8  19   0 [rcu_bh]
root         9 139   - [migration/0]
... ...

ps output sort on PID in descending order:

Code:

$ ps -eo user,pid,pri,ni,cmd --sort=-pid
USER       PID PRI  NI CMD
foffb    10943  19   0 less
foffb    10942  19   0 ps -eo user,pid,pri,ni,cmd --sort=-pid
foffb    10900  19   0 /usr/lib/firefox/plugin-container -greomni /usr/lib/firefox/omni.ja -appomni /usr/lib/firefox/browser/omni.ja -appdir /usr/lib/firefox/browser 2719 true tab
root     10884  19   0 [kworker/u8:2]
root     10871  19   0 [kworker/3:2]
foffb    10800  19   0 bash
.... ....

But ps does not sort on ascending pri.
It also does not sort on decending order for pri.

Code:

$ ps -eo user,pid,pri,ni,cmd --sort=pri
USER       PID PRI  NI CMD
root         1  19   0 /sbin/init splash
root         2  19   0 [kthreadd]
root         3  19   0 [ksoftirqd/0]
root         5  39 -20 [kworker/0:0H]
root         7  19   0 [rcu_sched]
root         8  19   0 [rcu_bh]
root         9 139   - [migration/0]
root        10 139   - [watchdog/0]
root        11 139   - [watchdog/1]
root        12 139   - [migration/1]
root        13  19   0 [ksoftirqd/1]
root        15  39 -20 [kworker/1:0H]
root        16 139   - [watchdog/2]

.....

Why?
Thank you.

MensaWater · 01-24-2017, 05:00 PM

You can pipe to the separate "sort" command to achieve what you want:

Sort on pri field (field 3) as a numeric field:

Code:

ps -eo user,pid,pri,ni,cmd |sort -nk3

Reverse the sort:

Code:

ps -eo user,pid,pri,ni,cmd |sort -rnk3

That sort command can be used for many things not just ps.

EDIT:
On doing tests it appears you have to spell out "priority" for the ps built in sort to work (i.e. don't just use "pri"):

Code:

ps -eo user,pid,pri,ni,cmd --sort=priority

Code:

ps -eo user,pid,pri,ni,cmd --sort=-priority

fanoflq · 01-24-2017, 05:43 PM

Thank you.

Quote:

Originally Posted by MensaWater

EDIT:
On doing tests it appears you have to spell out "priority" for the ps built in sort to work (i.e. don't just use "pri":

Code:

ps -eo user,pid,pri,ni,cmd --sort=priority

Code:

ps -eo user,pid,pri,ni,cmd --sort=-priority

FROM PS MAN PAGE:

Quote:

--sort spec
Specify sorting order. Sorting syntax is [+|-]key[,[+|-]key[,...]]. Choose a multi-letter key from the STANDARD FORMAT SPECIFIERS section. The "+" is optional since default direction is increasing numerical or lexicographic order. Identical to k. For example: ps jax --sort=uid,-ppid,+pid

Then I looked a "STANDARD FORMAT SPECIFIERS" section and picked "pri" under CODE column which corresponds to "PRI" under HEADER column.

So where did you find specific instruction to use the word "priority" as sort key?

MensaWater · 01-25-2017, 01:57 PM

Quote:

Originally Posted by fanoflq

So where did you find specific instruction to use the word "priority" as sort key?

I didn't. Being clever I knew "pri" was short for "priority" so decided to try that when I saw the same behavior (and man page) as you did.

My main reason for posting was to give you the other sort command's usage but was curious as to why the ps built in sort flag hadn't worked.

Glad I could help.

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