mjhjmtu

➥ When using top utility to view processes and their activity, how does one filter the list to a subset by name?

For example when I want to see only the processes with a name containing postgres or java.

I am using FreeBSD 11.2, but guidance across Unix flavors would be helpful if behavior varies.

I have read about using this:

top -p $(pgrep -d',' postgres)

…but I get an error:

Illegal variable name.

The top variant provided with FreeBSD core system does not have that -p option used to select a list of pid to watch on a pseudo real-time manner.

Nevertheless, the htop package can be installed on top of your FreeBSD system and this more colorfull top (among other things) variation have this wanted -p option.

• 
  htop help:

From htop usage:

htop 2.2.0 - (C) 2004-2018 Hisham Muhammad
Released under the GNU GPL.

-C --no-color Use a monochrome color scheme
-d --delay=DELAY Set the delay between updates, in tenths of seconds
-h --help Print this help screen
-s --sort-key=COLUMN Sort by COLUMN (try --sort-key=help for a list)
-t --tree Show the tree view by default
-u --user=USERNAME Show only processes of a given user
-p --pid=PID,[,PID,PID...] Show only the given PIDs
-v --version Print version info

• installing htop

using FreeBSD repository:

# pkg install htop

or through the ports:

# cd /usr/ports/sysutils/htop
# make install clean

Top in designed to show the top processes, hence the name. There are, however, some work arounds that might help you.

You can pipe the output to grep:

top | grep postgres

You could try the -o flag with a field name.

top -o pid

You can combine that with the -i flag, which takes you into interactive mode

top -io pid

Once there, you can toggle various options such as a for process titles, or u for user.

Try combining the various options.

Reference

man top

Freebsd 11.2 release