Lifehacker had a pretty neat post yesterday which added “a Handy Separator Between Commands in Your Terminal on Mac OS X and Linux.” I use a Cygwin terminal on my Windows machine, and the Linux script almost worked: the dashes didn’t print. I tracked down my particular problem to the COLUMNS variable used to calculate how many dashes to print in the separator. In my Cygwin terminal prompt, running “export $COLUMNS” showed the variable was blank; meaning that no dashes were used for the separator. Looking at the Mac modification, I noticed that it used the command “shopt -s checkwinsize” to check the window size and if necessary update the LINES and COLUMNS variables. So after adding these two lines to the beginning of the Linux “.bash_ps1″ script, here https://github.com/emilis/emilis-config/blob/master/.bash_ps1, the separator worked for my Cygwin terminal.
shopt -s checkwinsize export COLUMNS