help

Many packages have useful help messages built right into them. Here are a few ways to try and extract that information:

• $<$command$>$ -h
• $<$command$>$ -help
• $<$command$>$ +help
• $<$command$>$ -help
• $<$command$>$ -?
• type ``help'' or ``info'' after bringing up an interactive program (e.g. bash, gdb, gnuplot, etc).