In a single user situation, if we take the example of xterm, we can simply count the number of pids of xterm; xterm creates a separate pid for each and every window.
gnome-terminal however runs a single pid, but the good news is that it creates a child process for each and every window and/or tab. we can retrieve these child processes by the command:
pgrep -P <pid_of_gnome-terminal>
There are however a few complications to deal with:
Reading your question, we may assume, that user in this case is actually owner of the x-session. Usually we can simply use the $USER -variable, but this might not match the currently logged in user of $DISPLAY.
In a multi-user situation, pids belonging to the (either which) terminal application, do not necessarily belong to the current $DISPLAY. We need to split off only the relevant pids and child-pids.
On Unity (15.10 or lower), if a second user logs in, an additional process is started (gnome-pty-helper), which appears as a child process in gnome-terminal, but the process (obviously) has no window or tab. On Mate, the process exists anyway.
In short
To count the number of tabs and/or windows of a terminal application, we need to:
- See if we run a terminal application which has multiple pids or a single pid on one
$DISPLAY (x-session)
- From the running processes, split off only the relevant pids, running on this
$DISPLAY
- If the application runs child-processes for its pid (for windows/tabs), see if
gnome-pty-helper runs, to correct the number.
This can very well be scripted however, to reliably find the number of currently opened windows and/or tabs.
The script
In the script below, the targeted terminal application is used as an argument. The script works on many terminals I tested it on. An exception is Tilda at this moment.
An example
- I have two users logged in, one (not the current) with two
gnome-terminal windows, one (the one in the image) with three gnome-terminal windows, and two xterm windows.
The command:
/path/to/get_terms.sh gnome-terminal
outputs:
3
while
/path/to/get_terms.sh xterm
outputs:
2
The script
#!/bin/bash
terminal=$1
# get the user running the current x-session
username=$(who | grep $DISPLAY | head -1 | awk '{print $1}')
# get the pid of the terminal for the current user
userpid=$(pgrep -u $username $terminal)
# check what type the terminal is (multi pid/single pid)
npids="$(echo "$userpid" | wc -w)"
# in case of a single pid, count the children
if [ "$npids" -eq 1 ]; then
# check if gnome-pty-helper runs (starts when multiple users are logged in)
ptpid=$(pgrep gnome-pty-helpe)
# get number of child- procs
let "orig = $( pgrep -P $(pgrep -u $username $terminal) | wc -w )"
# if pty-helper runs, correct the number of child procs
if [ -n "$ptpid" ] && [ -n "$userpid" ]; then
let "n_terms = $orig-1"; else let "n_terms = $orig"
fi
# if no child procs run, n-terminals = n-counted pids (difference Mate <> Unity)
if [ "$n_terms" -eq 0 ]; then echo $orig; else echo $n_terms; fi
# in case of multiple pids, count the pids
elif [ "$npids" -gt 1 ]; then echo $npids
fi
To use
Copy the script into an empty file, save it as get_terms.sh, make it executable and run it by the command:
/path/to/get_terms.sh <terminal_application>
