runon: Run an X program on a different workspace

#!/bin/zsh

# Usage:
#
# runon <workspace> <command...>
#
# This will run the given command, then move the resulting window to the
# workspace specified. There are two formats for workspace:
#   +n or -n: Move the window n desktops to the right (+) or left (-)
#   name:     Move the window to the desktop with the given name
#

# Check for the required parameters
if [ $# -lt 2 ]
then
    echo 'Workspace and command are required.' >&2
    exit 1
fi

# Get the workspace from the arguments, then remove it
workspace=$1; shift 1

# If the workspace starts with a + or a -, assume it's an offset
if [[ "$workspace" =~ '^[+-][[:digit:]]*$' ]]
then
    # Get the current desktop id
    wmctrl -d | awk "/*/ {print \$1}" | read current

    # Add the offset to that id
    desk=$((current + workspace))

    # If that desktop id does not exist, error out
    if ! wmctrl -d | grep -q "^$desk"
    then
        echo "Offset does not resolve to a valid workspace" >&2
        exit 1
    fi
else
    # Resolve a workspace to desktop id
    if ! wmctrl -d | awk "{if (\$9 == \"$workspace\") print \$1}" | read desk
    then
        # If that fails, error out
        echo "Unknown workspace $workspace" >&2
        exit 1
    fi
fi

# Start the command, capturing its PID
$@ &; pid=$!

# Loop while that command is running
while jobs %1
do
    # If it has any windows, move them to the requested workspace then
    # terminate the loop
    if wmctrl -l -p | awk "{if (\$3 == $pid) print \$1}" | read xid
    then
        wmctrl -i -r $xid -t $desk
        break
    fi

    # Wait a little while for a window
    sleep 1
done &>/dev/null &

# Wait for the command to exit
wait %1 &>/dev/null