"With seemingly countless commands available from the UNIX command line—a quick, cursory accounting yields more than 1,500—and each of those with a raft of features, it's impossible to remember every option, nuance, and permutation. Worse, because the universe of UNIX commands evolved over a 40-year period, there are few punctilios. For example, -l means "long format" in ls, but other file-related utilities do not assign the same meaning to the option, if that option is available at all. Further, and ironically, some command-line programs support --help, which prints a terse usage hint, but not all do. As powerful as the command line is, the learning curve can be proportionally maddening.
"At least at first. Over time, like learning any skill, oft-used command permutations become instinctual and part of muscle memory. Moreover, depending on the shell you use, you can commit a frequently used command-line combination to an alias or a shell script, reducing the burden on your memory. Some shells also maintain lengthy histories that persist previously used commands session over session.
"Alas, memory fades and new challenges arise. To truly master the command line, you can't fight the man. The man system, that is, UNIX's built-in, online reference system. In fact, the UNIX community has a longstanding mantra reserved for the most confounding problems: "RTFM!" or "Read the frickin' man page!"
