Split Windows

The split-window statements in lines 47 and 48 with the -h (horizontal) and -v (vertical) options create additional panes in the window by dividing the window horizontally and vertically. Tmux numbers windows and panes from 0 up – but be careful, a frequently used Tmux configuration option changes the start point of the enumeration to 1!

In other words, to address the second pane of the first window in the log4perl session of a newly installed Tmux, line 55 uses log4perl:0.1; it then issues send-keys to run the command for the test suite, followed by a closing C-m (for Return). However, you could just as easily use vagrant ssh to change to a Vagrant VM, as described in the previous issue of this Perl column [4], and ensure that the test suite is running in a virtual cleanroom. Line 51 finds the first two .pm files in the hierarchy of the selected Perl project and passes in their names to the vim editor with the -p option, which displays them in tabs in the left-hand pane (Figure 2).

Figure 2: A Tmux window with an editor, a test suite, and a test file.

Installation

Tmux is included in many distributions' repositories; on Ubuntu, the command

sudo apt-get install tmux

will do the trick. Because the Tmux developers seem to have been very busy of late, users will want to go for version 1.7 at least – or even 1.8 – to take advantage of all the features introduced in this article. If you prefer a more DIY approach, you can pick up the source code [2] and build your own version. The only important dependencies are for libevent (at least 1.4.14 or 2.0) and ncurses. A Bash script available at GitHub [5] automates the build process.

Brian Hogan's book [6] provides useful tips for common tasks – from developer environments through pair programming, wherein two developers in two locations type in different panes in the same session. Even better: If you check the script into your source control system, the next engineer can simply fire up the development environment and start working productively right away.