This morning I was trying to install Gnuplot from source because I wanted generate some graphs for ApacheBench. I’m currently benchmarking one of our Rails applications using Nginx w/ Mongrels against Phusion Passenger (Nginx flavor). When “make”ing Gnuplot I received the following error:

Undefined symbols:
“_rl_ding”, referenced from:
_alert in mouse.o
“_rl_complete_with_tilde_expansion”, referenced from:
_main in plot.o
“_history_list”, referenced from:
_write_history_list in history.o
“_rl_reset_after_signal”, referenced from:
_main in plot.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make[3]: *** [gnuplot] Error 1
make[2]: *** [all-recursive] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

After reading a comment here I found out that the -–with-readline=builtin option needs to be include when configuring Gnuplot. So you should run the following before “make”ing:

./configure -–with-readline=builtin

That got me going and hopefully it will do the same for you!

If you’re new to Git you may be working on a branch and realize that you’ve fallen out of synch with the master. In the case of Subversion you can normally do “svn up” and be good to go. In the case git you’ll normally do a “git fetch” and then a “git status” shows the following:

Your branch is behind ‘origin/master’ by 12 commits, and can be fast-forwarded.

To sync your branch with the master you can issue the following command:

git merge master

and you should now have all the latest changes from master.