fc - Process a command history list

Format

  • fc [-r] [-e editor] [first[last]]
  • fc -l [-nr] [first[last]]
  • fc -s [old=new] [specifier]

Description

fc displays, edits, and reenters commands that have been input to an interactive shell. fc stands for fix commands. If the variable HISTSIZE is not defined, 128 commands are accessible. The number of commands that are accessible is determined by the HISTSIZE variable.

The shell stores these commands in a history file. When the HISTFILE environment variable is defined as the name of a writable file, the shell uses this as the history file. Otherwise, the history file is $HOME /.sh_history, if HOME is defined and the file is writable. If the HOME variable is not defined, or the file is not writable, the shell attempts to create a temporary file for the history. If a temporary file cannot be created, the shell does not keep a history file.
Note: A shell shares history (commands) with all shells that have the same history file. A login shell truncates the history file if it is more than HISTSIZE lines long.
Normally, the shell does not keep a history of commands run from a profile file or the ENV file. By default, however, it begins recording commands in the history file when it encounters a function definition in either of these setup files. This means that the HISTSIZE and HISTFILE variables must be set up appropriately before the first function definition. If you do not want the history file to begin at this time, use: 
set -o nolog

For more information, see sh and set. Any variable assignment or redirection that appears on the fc command line affects both the fc command itself and the commands that fc produces.

The first form of fc in Format puts you into an editor with a range of commands to edit. When you leave the editor, fc inputs the edited commands to the shell.

The first and last command in the range are specified with first and last. There are three ways to specify a command.
  • If the command specifier is an unsigned or positive number, fc edits the command with that number.
  • If the command specifier is a negative number, n, fc edits the command that came n commands before the current command.
  • If the command specifier is a string, fc edits the most recent command beginning with that string.

The default value of last is first. If you specify neither first nor last, the default command range is the previous command entered to the shell.

Options

-e editor
Invokes editor to edit the commands. If you do not specify the -e option, fc assumes that the environment variable FCEDIT, if defined, contains the name of the editor for fc to use. If FCEDIT is not defined, fc invokes ed to edit the commands.
-l
Displays the command list. This option does not edit or reenter the commands. If you omit last with this option, fc displays all commands from the one indicated by first through to the previous command entered. If you omit both first and last with this option, the default command range is the 16 most recently entered commands.
-n
Suppresses command numbers when displaying commands.
-r
Reverses the order of the commands in the command range.
-s
Reenters exactly one command without going through an editor. If a command specifier is given, fc selects the command to reenter as described earlier; otherwise, fc uses the last command entered. To perform a simple substitution on the command before reentry, use a parameter of the form old=new. The string new replaces the first occurrence of string old. fc displays the (possibly modified) command before reentering it.

Environment variables

FCEDIT
Contains the default editor to be used if none is specified with the -e option.
HISTFILE
Contains the path name of the history file.
HISTSIZE
Gives the maximum number of previous commands that are accessible.

Files

/tmp
Used to store temporary files. You can use the TMPDIR environment variable to dictate a different directory to store temporary files.
$HOME/.sh_history
This default history file is created.

Localization

fc uses the following localization environment variables:
  • LANG
  • LC_ALL
  • LC_CTYPE
  • LC_MESSAGES
  • NLSPATH

Usage notes

  1. fc is a built-in shell command.
  2. r is a built-in alias for fc -s. history is a built-in alias for fc -l.

Exit values

0
If you specified -l, this indicates successful completion.
1
Failure due to any of the following reasons:
  • Missing history file.
  • Inability to find the desired line in the history file.
  • Inability to create temporary file.
2
An incorrect command-line option or argument.

If fc runs one or more commands, the exit status of fc is the exit status of the last run command.

Messages

Possible error messages include:
Cannot create temporary file
fc must create a temporary file to do some operations, such as editing. It prints this message when it cannot create its temporary file because the disk is full, for example.
No command matches string
You asked to edit a command beginning with a particular string, but there was no such command in the history file.

Portability

POSIX.2.

Related information

alias, ed, print, read, sh, vi