Fc (Unix)

fc is a standard program on Unix and Unix-like operating systems that lists, edits and reexecutes commands previously entered to an interactive shell. fc is a builtin command in the Bash and Zsh shells and is an initialism for "fix command". It is particularly helpful for editing complex, multi-line commands. The editor can be specified by setting the EDITOR (changes the default editor) or the FCEDIT environment variable.

Examples
Flag  used to list previous command history, with example showing command   as item 1001 in the user's history.

Flag  with this index would then recall the history command from 1001:

Though more powerfully,  enables inline substitution.

Most powerfully, executing fc on its own edits the last command executed. Editor can be specified on command line (-e) or via environment variable FCEDIT. User is thus able to fully modify the last command executed via the editor, upon exiting will execute the resultant command.