Readline (简体中文)

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Readline 是来自 GNU Project 的库,Bash 和其他命令行界面的程序使用它在命令行编辑和交互。详情请参阅 readline(3)

安装

readline 包很可能已作为 Bash 的依赖安装。

编辑模式

Readline 默认使用 Emacs 风格的快捷键与命令行交互。不过,vi 风格的编辑界面也受支持,但需要将以下内容添加到 ~/.inputrc

~/.inputrc
set editing-mode vi

或者,要只为 Bash 设置,你可将以下内容添加到 ~/.bashrc

~/.bashrc
set -o vi

提示中的模式指示符

Vi 风格的编辑有两种模式:命令模式和插入模式。你可通过添加以下命令显示当前的模式:

~/.inputrc
set show-mode-in-prompt on

这将在你的提示中显示模式(默认是 (cmd)/(ins)),显示的内容可通过 vi-ins-mode-stringvi-cmd-mode-string 变量自定义。

为每个模式指定不同的光标样式

你可以使用"\1 .. \2" 转义符为每个模式指定不同的光标样式:

~/.inputrc
set vi-ins-mode-string \1\e[6 q\2
set vi-cmd-mode-string \1\e[2 q\2

这将在命令模式中显示方块形状的光标,在插入模式中显示竖线形状的光标。注意,你必须先启用模式指示符(见#提示中的模式指示符)。

Virtual Console 使用不同的转义代码,因此你应先检查使用的是哪种终端:

~/.inputrc
$if term=linux
	set vi-ins-mode-string \1\e[?0c\2
	set vi-cmd-mode-string \1\e[?8c\2
$else
	set vi-ins-mode-string \1\e[6 q\2
	set vi-cmd-mode-string \1\e[2 q\2
$endif

详情请参阅 software cursor for VGA

Fast word movement

Xterm 默认支持使用 Ctrl+LeftCtrl+Right 在单词间移动。要在其他终端模拟器中实现这一效果,先找到正确的终端代码,然后在 ~/.inputrc 中绑定到 backward-wordforward-word

例如,对于 urxvt

~/.inputrc
"\e[1;5D": backward-word
"\e[1;5C": forward-word

历史

通常,无论你输入了什么,按向上箭头都会出现上一次输入的命令。然而,用户可能会觉得只显示匹配刚刚输入的内容的命令更实用。

例如,假设输入了以下命令:

  • ls /usr/src/linux-2.6.15-ARCH/kernel/power/Kconfig
  • who
  • mount
  • man mount

此时,当输入 ls 并按向上箭头,输入将会被替换为 man mount。如果你使用了历史搜索功能,那么只有过去以 ls(当前的输入)开头的命令会被显示,在这里就是 ls /usr/src/linux-2.6.15-ARCH/kernel/power/Kconfig

要启用历史搜索功能,只需把以下内容加入到 /etc/inputrc 或者 ~/.inputrc

"\e[A": history-search-backward
"\e[B": history-search-forward

如果你使用 vi 模式,添加以下内容到 ~/.inputrc(来自这个帖子):

set editing-mode vi
$if mode=vi
set keymap vi-command
# these are for vi-command mode
"\e[A": history-search-backward
"\e[B": history-search-forward
j: history-search-forward
k: history-search-backward
set keymap vi-insert
# these are for vi-insert mode
"\e[A": history-search-backward
"\e[B": history-search-forward
$endif

如果你选择将这些内容添加到 ~/.inputrc,那建议你同时在文件的开始添加以下内容,以避免像这样的怪事:

$include /etc/inputrc

Alternatively, one can use reverse-search-history (incremental search) by pressing Ctrl+R, which does not search based on previous input but instead jumps backwards in the history buffer as commands are typed in a search term. Pressing Ctrl+R again during this mode will display the previous line in the buffer that matches the current search term, while pressing Ctrl+G (abort) will cancel the search and restore the current input line. So in order to search through all previous mount commands, press Ctrl+R, type 'mount' and keep pressing Ctrl+R until the desired line is found.

The forward equivalent to this mode is called forward-search-history and is bound to Ctrl+S by default. Beware that most terminals override Ctrl+S to suspend execution until Ctrl+Q is entered. (This is called XON/XOFF flow control). For activating forward-search-history, either disable flow control by issuing:

$ stty -ixon

或者在 inputrc 中使用不同的键。例如,要使用默认未绑定的 Alt+S

"\es": forward-search-history

Faster completion

When performing tab completion, a single tab attempts to partially complete the current word. If no partial completions are possible, a double tab shows all possible completions.

The double tab can be changed to a single tab by setting:

~/.inputrc
set show-all-if-unmodified on

Or you can set it such that a single tab will perform both steps: partially complete the word and show all possible completions if it is still ambiguous:

~/.inputrc
set show-all-if-ambiguous on

Colorized completion

You can enable coloring of completion of filenames with the colored-stats option. You can also color the identical prefix of completion-lists with colored-completion-prefix. For example:

~/.inputrc
# Color files by types
# Note that this may cause completion text blink in some terminals (e.g. xterm).
set colored-stats On
# Append char to indicate type
set visible-stats On
# Mark symlinked directories
set mark-symlinked-directories On
# Color the common prefix
set colored-completion-prefix On
# Color the common prefix in menu-complete
set menu-complete-display-prefix On

Readline also supports binding keys to keyboard macros. For simple example, run this command in Bash:

bind '"\ew": "\C-e # macro"'

or add the part within single quotes to inputrc:

"\ew": "\C-e # macro"

Now type a line and press Alt+W. Readline will act as though Ctrl+E (end-of-line) had been pressed, appended with ' # macro'.

Use any of the existing keybindings within a readline macro, which can be quite useful to automate frequently used idioms. For example, this one makes Ctrl+Alt+L append "| less" to the line and run it (Ctrl+M is equivalent to Enter):

"\e\C-l": "\C-e | less\C-m"

The next one prefixes the line with 'yes |' when pressing Ctrl+Alt+Y, confirming any yes/no question the command might ask:

"\e\C-y": "\C-ayes | \C-m"

This example wraps the line in su -c '', if Alt+S is pressed:

"\es": "\C-a su -c '\C-e'\C-m"

This example prefixes the line with sudo , if Alt+S is pressed. It is safer because it will not input the Enter key.

"\es": "\C-asudo \C-e"

As a last example, quickly send a command in the background with Ctrl+Alt+B, discarding all of its output:

"\e\C-b": "\C-e > /dev/null 2>&1 &\C-m"

禁用 control 回显

Readline 使得终端在按下 Ctrl+C 后回显 ^C。要禁用,只需将以下内容添加到 ~/.inputrc

set echo-control-characters off

参阅