Command history

Article summary

Command history is a feature in many operating system shells, computer algebra programs, and other software that allows the user to recall, edit and rerun previous commands. Command line history was added to Unix in Bill Joy's C shell of 1978; Joy took inspiration from an earlier implementation in Interlisp. It quickly became popular because it made the C shell fast and easy to use. History has since become a standard feature in other shells, including ksh, Bash and Microsoft's cmd.exe. History addressed two important scenarios: # Executing the same command or a short sequence of commands over and over. An example might be a developer frequently compiling and running a program. # Correcting mistakes or rerunning a command with only a small modification. In Joy's original C shell, the user could refer to a previous command by typing an exclamation, ! , followed by additional characters to specify a particular command, only certain words, or to edit it in some way before pasting it back into the command line. For example: : !! meant the entire previous command. : !$ meant just the last word of the previous command. : !abc meant the command that started with abc. The usual implementation today is to combine history with command-line editing.…

Key claims

No claims recorded.

Discussion questions

1. Summarise the article in your own words. Which single claim would you verify first, and why?
2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

Bibliography

No sources recorded.