Really simple task (i.e. Rake) timing in Bash

gistfile1.bash

# Just copy this line into your terminal
# Replace "clear ; rake" with whatever command(s) you want to time.
start=`date +'%s'` ; clear ; rake ; end=`date +'%s'`;  echo \*\*\* Task took `expr $end - $start` seconds to run.

# Even better, add this to your ~/.bash_profile (or similar) file:
function timer() {
  start=`date +'%s'`;
  $@
  end=`date +'%s'`;
  echo \*\*\* Task took `expr $end - $start` seconds to run.;
}

# Reload your bash profile by restarting terminal or type 
source ~/.bash_profile

# then run the timer using
timer your_command_here

# For example, running:
timer sleep 3
# outputs:
# *** Task took 3 seconds to run.

# This only works for single commands at the moment, and will break and/or be inaccurate if you use pipes or semicolons.