pstree command usage example

$pidof systemd
1461 1059
$pstree 1461
systemd─┬─(sd-pam)
        ├─at-spi-bus-laun─┬─dbus-daemon
        │                 └─3*[{at-spi-bus-laun}]
        ├─at-spi2-registr───2*[{at-spi2-registr}]
        ├─dbus-daemon
        ├─dconf-service───2*[{dconf-service}]
        ├─evolution-addre─┬─evolution-addre───5*[{evolution-addre}]
        │                 └─4*[{evolution-addre}]
        ├─evolution-calen─┬─evolution-calen───9*[{evolution-calen}]
        │                 └─4*[{evolution-calen}]
        ├─evolution-sourc───3*[{evolution-sourc}]
        ├─gnome-shell-cal───5*[{gnome-shell-cal}]
        ├─gnome-terminal-─┬─bash───pstree
        │                 └─3*[{gnome-terminal-}]
        ├─goa-daemon───4*[{goa-daemon}]
        ├─goa-identity-se───3*[{goa-identity-se}]
        ├─gvfs-afc-volume───3*[{gvfs-afc-volume}]
        ├─gvfs-goa-volume───2*[{gvfs-goa-volume}]
        ├─gvfs-gphoto2-vo───2*[{gvfs-gphoto2-vo}]
        ├─gvfs-mtp-volume───2*[{gvfs-mtp-volume}]
        ├─gvfs-udisks2-vo───2*[{gvfs-udisks2-vo}]
        ├─gvfsd───2*[{gvfsd}]
        ├─gvfsd-fuse───5*[{gvfsd-fuse}]
        ├─gvfsd-metadata───2*[{gvfsd-metadata}]
        ├─mission-control───3*[{mission-control}]
        ├─pulseaudio───2*[{pulseaudio}]
        └─tracker-store───7*[{tracker-store}]
$pstree 1059
systemd─┬─(sd-pam)
        ├─at-spi-bus-laun─┬─dbus-daemon
        │                 └─3*[{at-spi-bus-laun}]
        ├─at-spi2-registr───2*[{at-spi2-registr}]
        ├─dbus-daemon
        └─pulseaudio───2*[{pulseaudio}]
$

$pstree `pidof systemd | awk '{print $2}'`
systemd─┬─(sd-pam)
        ├─at-spi-bus-laun─┬─dbus-daemon
        │                 └─3*[{at-spi-bus-laun}]
        ├─at-spi2-registr───2*[{at-spi2-registr}]
        ├─dbus-daemon
        └─pulseaudio───2*[{pulseaudio}]
$