Manolo Gouy's SeaView editor is a good alternative to GCG's SeqLab editor. It can not launch all of the other applications that SeqLab can, but it can run all of the multiple sequence alignment routines on HPC as "External Methods" and it can perform pairwise dot-plot analyses.

Using SeaView on HPC

The SeaView editor is launched by typing its name in lower case:

seaview & 

The ampersand "&" is not necessary but allows you to retain control of your terminal window by launching SeaVew as a background process. Be sure to use an X-tunnelled ssh session to connect to HPC, if you want to use SeaView. SeaView recognizes several standard multiple sequence file formats. Help is available within the program. The NIH also has a decent SeaView page.