I know that we can easily find the following:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
of all the running processes by using the command:
sudo ps aux
My, question is that, is it possible to show the output of only the column under COMMAND and nothing else?
Use -o flag.
To list only your own processes
ps -o command
To list all system processes
ps -e -o command
This is not the only way to list commands, they can either be printed with command line flags, or as executable only (which is what command option does).
From my comment bellow the answer:
command, args, and cmd all give full command. In fact man page states command and cmd are aliases for args , with the - flags included. The comm gives the name of the exacutable only. Aliases to that are ucmd and ucomm. I misread about AIX options, those can be actually specified with printf-like format, %a for args, %c for comm
Refer to man ps for more info on usage and available format options
Programmatic approach would be a bit redundant , since ps already provides us with the formatting options, but it can be done with awk, which is much useful when dealing with columnized output.
ps aux | awk '{ for(i=1;i<=NF;i++) {if ( i >= 11 ) printf $i" "}; printf "\n" }'
Note however, that this code breaks if username contains whitespace, e.g. john doe. This can be amended with adding gsub function that will elimiate your username from the ps list. However, if there is multiple users logged into system, that may be difficult to errase all of the usernames from the output. Thus, you can see that -o flag is much more preferred.
Side note, sudo is not necessary to for listing all processes with ps
ps -eo command & ps -eo comm? The only difference I found was in command the output was as such: [kthreadd] whereas in comm the output was as this: kthreadd. Does this signify anything?
comm is AIX format, where as command is standard GNU style format. AIX is another *NIX like system, so that option may be used for compatability. Otherwise, no difference
Nov 18, 2015 at 7:24
diff <(ps -eo comm) <(ps -eo command) and there seems to be quite a rattle down there, can you clarify?
command, args, and cmd all give full command. In fact man page states command and cmd are aliases for args , with the - flags included. The comm gives the name of the exacutable only. Aliases to that are ucmd and ucomm. I misread about AIX options, those can be actually specified with printf-like format, %a for args, %c for comm
Nov 18, 2015 at 8:08
A more generic way. We determine the column of the command. In this way, it does not matter which switches are used for ps.
ps ax | awk -v p='COMMAND' 'NR==1 {n=index($0, p); next} {print substr($0, n)}'
Sample output
% ps aux | awk -v p='COMMAND' 'NR==1 {n=index($0, p); next} {print substr($0, n)}'
/sbin/init splash
[kthreadd]
[ksoftirqd/0]
[kworker/0:0H]
[rcu_sched]
[rcu_bh]
[migration/0]
[watchdog/0]
[watchdog/1]
[migration/1]
[ksoftirqd/1]
[kworker/1:0H]
[watchdog/2]
[migration/2]
[ksoftirqd/2]
[kworker/2:0H]
[khelper]
[kdevtmpfs]
[netns]
[perf]
[khungtaskd]
[writeback]
[ksmd]
[khugepaged]
[crypto]
[kintegrityd]
[bioset]
[kblockd]
[ata_sff]
[md]
[devfreq_wq]
[kswapd0]
[fsnotify_mark]
[ecryptfs-kthrea]
[kthrotld]
[acpi_thermal_pm]
[scsi_eh_0]
[scsi_tmf_0]
[scsi_eh_1]
[scsi_tmf_1]
[ipv6_addrconf]
[deferwq]
[charger_manager]
[kpsmoused]
[scsi_eh_2]
[scsi_tmf_2]
[kworker/0:1H]
[jbd2/sda1-8]
[ext4-rsv-conver]
[kauditd]
[kworker/0:2]
/lib/systemd/systemd-journald
/lib/systemd/systemd-udevd
[…]
And what's about pstree?
Sample output
% pstree -alU
systemd splash
├─ModemManager
│ ├─{gdbus}
│ └─{gmain}
├─NetworkManager --no-daemon
│ ├─dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/sendsigs.omit.d/network-manager.dhclient-eth0.pid -lf /var/lib/NetworkManager/dhclient-57cfb005-1dc6-410d-aebc-16d8d152abfd-eth0.lease -cf /var/lib/NetworkManager/dhclient-eth0.conf eth0
│ ├─dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/run/sendsigs.omit.d/network-manager.dnsmasq.pid --listen-address=127.0.1.1 --conf-file=/var/run/NetworkManager/dnsmasq.conf --cache-size=0 --proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq --conf-dir=/etc/NetworkManager/dnsmasq.d
│ ├─{gdbus}
│ └─{gmain}
├─VBoxClient --clipboard
│ └─VBoxClient --clipboard
│ └─{SHCLIP}
├─VBoxClient --display
│ └─VBoxClient --display
│ └─{VT_MONITOR}
├─VBoxClient --seamless
│ └─VBoxClient --seamless
│ └─{X11 events}
├─VBoxClient --draganddrop
│ └─VBoxClient --draganddrop
│ ├─{dndHGCM}
│ └─{dndX11}
├─VBoxService --pidfile /var/run/vboxadd-service.pid
│ ├─{automount}
│ ├─{control}
│ ├─{cpuhotplug}
│ ├─{memballoon}
│ ├─{timesync}
│ ├─{vminfo}
│ └─{vmstats}
├─VBoxService
│ ├─{automount}
│ ├─{control}
│ ├─{cpuhotplug}
│ ├─{timesync}
│ ├─{vminfo}
│ └─{vmstats}
├─accounts-daemon
│ ├─{gdbus}
│ └─{gmain}
├─agetty --noclear tty1 linux
├─apache2 -k start
│ ├─apache2 -k start
│ ├─apache2 -k start
│ ├─apache2 -k start
│ ├─apache2 -k start
│ └─apache2 -k start
├─at-spi-bus-laun
│ ├─dbus-daemon --config-file=/etc/at-spi2/accessibility.conf --nofork --print-address 3
│ ├─{dconf worker}
│ ├─{gdbus}
│ └─{gmain}
├─at-spi2-registr --use-gnome-session
│ ├─{gdbus}
│ └─{gmain}
├─atd -f
├─avahi-daemon
│ └─avahi-daemon
├─cgmanager -m name=systemd
├─colord
│ ├─{gdbus}
│ └─{gmain}
├─console-kit-dae --no-daemon
│ ├─62*[{console-kit-dae}]
│ ├─{gdbus}
│ └─{gmain}
├─cron -f
├─cups-browsed
│ ├─{gdbus}
│ └─{gmain}
├─cupsd -l
│ └─dbus dbus://
├─dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
├─dnsmasq -u lxc-dnsmasq --strict-order --bind-interfaces --pid-file=/run/lxc/dnsmasq.pid --listen-address 10.0.3.1 --dhcp-range 10.0.3.2,10.0.3.254 --dhcp-lease-max=253 --dhcp-no-override --except-interface=lo --interface=lxcbr0 --dhcp-leasefile=/var/lib/misc/dnsmasq.lxcbr0.leases --dhcp-authoritative
├─gdm
│ ├─gdm-session-wor
│ │ ├─gdm-x-session /usr/bin/gnome-session --autostart /usr/share/gdm/greeter/autostart
│ │ │ ├─Xorg vt7 -displayfd 3 -auth /run/user/120/gdm/Xauthority -nolisten tcp -background none -noreset -keeptty -verbose 3
│ │ │ │ ├─{llvmpipe-0}
│ │ │ │ ├─{llvmpipe-1}
│ │ │ │ └─{llvmpipe-2}
│ │ │ ├─dbus-daemon --print-address 4 --session
│ │ │ ├─gnome-session-b --autostart /usr/share/gdm/greeter/autostart
│ │ │ │ ├─gnome-settings-
│ │ │ │ │ ├─{dconf worker}
│ │ │ │ │ ├─{gdbus}
│ │ │ │ │ ├─{gmain}
│ │ │ │ │ └─{pool}
│ │ │ │ ├─gnome-shell --mode=gdm
│ │ │ │ │ ├─ibus-daemon --xim --panel disable
│ │ │ │ │ │ ├─ibus-dconf
│ │ │ │ │ │ │ ├─{dconf worker}
│ │ │ │ │ │ │ ├─{gdbus}
│ │ │ │ │ │ │ └─{gmain}
│ │ │ │ │ │ ├─ibus-engine-sim
│ │ │ │ │ │ │ ├─{gdbus}
│ │ │ │ │ │ │ └─{gmain}
│ │ │ │ │ │ ├─{gdbus}
│ │ │ │ │ │ └─{gmain}
│ │ │ │ │ ├─{JS GC Helper}
│ │ │ │ │ ├─{JS Sour~ Thread}
│ │ │ │ │ ├─{Sync}
│ │ │ │ │ ├─{dconf worker}
│ │ │ │ │ ├─{gdbus}
│ │ │ │ │ ├─{gmain}
│ │ │ │ │ ├─{llvmpipe-0}
│ │ │ │ │ ├─{llvmpipe-1}
│ │ │ │ │ ├─{llvmpipe-2}
│ │ │ │ │ └─{threaded-ml}
│ │ │ │ ├─{dconf worker}
│ │ │ │ ├─{gdbus}
│ │ │ │ └─{gmain}
│ │ │ ├─{gdbus}
│ │ │ └─{gmain}
│ │ ├─{gdbus}
│ │ └─{gmain}
[…]
I found a bashy way to achieve this from here
sudo ps aux | rev | cut -d ' ' -f 1 | rev
rev reverses the output of ps and then cut can help you out delimiting the first field(which is the last!) and then reverse it again...
worked for me.
ps aux itself will be listed as aux.
sudo isn't necessary for ps and the command crops a lot of the commands, so it's not very accurate, if you would like to work with colums , use awk it's much better for that task. In fact, the exact command would be ps aux | awk '{ for(i=1;i<=NF;i++) {if ( i >= 11 ) printf $i" "}; printf "\n" }'
Nov 18, 2015 at 7:09
awk should work it.
sudo ps and I thought awk would be too complicated for this task and came out with cut. Anyways, shouldn't you update your answer with that code so the OP can accept it?
ps it's just not blindly parsable. I think the only safe method here is ps -e -o.