Command to activate (either run or bring to front if already running) a program

A little bash and xdotool should do the trick. Notes on installing xdotool at end of post.

ActivateOrLaunch.sh

#!/usr/bin/env bash

# usage:
#    ActivateOrLaunch.sh firefox-bin
#
# Will launch firefox-bin or activate the first window in the windows stack
# --- Remember to chmod a+x ActivateOrLaunch.sh in order to execute.

# pgrep looks through the currently running processes and lists the process
#       IDs which matches the selection criteria to stdout
#       for more information on pgrep http://linux.die.net/man/1/pgrep

# if process is found by pgrep then pipe through head to get firt instance in
#    case of multiple processes running. If process not found $pid will be empty
pid=$(pgrep ${1} | head -n 1)

# Using "-z" check if $pid is empty, if so execute the process
if [ -z "$pid" ]; then
   echo "$1 not running... executing..."
   $1 &
else
   # process was found, find the first visible window and activate it
   echo "Found process $1 with PID $pid"

   # using xdotool [http://www.semicomplete.com/projects/xdotool/] get the first
   # visible windows using $pid. Redirect stderr to /dev/null and only select
   # the first visible windows using head
   wid=$(xdotool search --onlyvisible --pid $pid 2>/dev/null | head -n 1)

   # if $wid is empty the process does not have any visible windows... do nothing
   if [ -z "$wid" ]; then
     echo "Didn't find any visible windows for process $1 with PID: $pid"
   else
     # send the window id ($wid) from the window stack to xdotool
     echo "Activating first windows in stack"
     xdotool windowactivate $wid
   fi
fi

# ******** NOTES **********
# In order for this script to work correctly you need to pass the complete process 
# name for it to find any visible windows. The process needs needs to be in the path
# for it to execute if not running.
#
# For example
#
# If you try it with firefox-bin on Ubuntu 10.10 it will find the running process and 
# activate the window, but it will not be able to launch the process since the executable 
# in the path is called firefox which is a link to firefox.sh
# (/usr/bin/firefox -> ../lib/firefox-3.6.12/firefox.sh) which in turn executes firefox-bin
# (not in path).
#
# Next, if you use firefox it will find a process but won't be able to find any windows 
# since it's a wrapper function calling firefox-bin and doesn't have any windows. 

You can find the code on github

I tested the code on Ubuntu 10.10 (Gnome) and it worked. It need some polishing since I just typed it up and wasn't worried about making it pretty (wanted to make sure to get the comments in)

To install xdotool you can apt-get install xdotool (form me this fetched version 2.20100701.2691), if you want the latest and greatest get it from here (as of 20101116 it's as version 2.20101012.3049-4)

Create a file in your home directory called sql-raise.sh

#!/bin/sh
if ps -ef | grep process-name | grep -v grep ; then
    #The process is running, bring it to the front
    xdotool search --name process-name windowraise
    exit 0
fi

#The process is not running, start it
process-name

The line starting if ps -ef... translates to:

• List all processes which are running
• Filter out any lines which don't contain process-name
• Filter out the grep command itself, to prevent false positives

The line starting xdotool is the one which brings the process to the front.

On a command line execute chmod +x ~/sql-raise.sh to make the file executable.

To bind this to a key, use the System -> Preferences -> Keyboard Shortcuts

'launchorsitch.sh firefox' starts firefox if it isn't running, switches to it, if it isn't active or minimizes it if it's the active window.

#!/bin/bash
# usage: "launchorswitch.sh xterm" to change to/start/hide xterm
app=$1
app_win_id=`wmctrl -lx|grep -i $app|cut -d ' ' -f 1`
case $app in
    terminator)
        app_exec="terminator --geometry=1000x720+140+28"
    ;;
    *)
        app_exec=$app
    ;;
esac
if [ -z $app_win_id ]; then
    $app_exec & # app not started, so start it
else

    active_win_id=`wmctrl -r :ACTIVE: -e 0,-1,-1,-1,-1 -v 2>&1|grep U|cut -d ' ' -f 3`
    if [ $app_win_id == $active_win_id ]; then
        wmctrl -r :ACTIVE: -b toggle,hidden    # hide app when active
    else
        wmctrl -i -a $app_win_id    #switch to app
    fi;
fi;

At the beginning there are special rules for programs (here it's terminator). My hack uses wmctrl and allows to specify special rules for what executable to look for/run. Any comments on style, obvious mistakes etc welcome.