Learn about case sensitivity issues in Linux and MacOS terminals in simple terms (with code)

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Linux and MacOS terminal prompts that case is not sensitive

Open the terminal and cdgo to userhome Directory, enter:

echo "set completion-ignore-case on" >> .inputrc

Close and reopen the terminal

If you just want to quickly solve the above problem, just look at the third part.

inputrc file introduction

Bash and most other shell use the Readline library as their input-related library. The Readline library has some default keymaps. In addition, you can also customize the keymap by modifying the inputrc file. The

inputrc file is the startup file of the Readline library. When a program that uses Readline as the input library starts, it will automatically readinputrcConfiguration file, initialize customized keyboard mapping.

inputrcThe location of the file is controlled by the shell environment variable INPUTRC. If this variable is not set, the default inputrcThe path of the file is ~/.inputrc.

If the file ~/.inputrc does not exist, the system-level (effective for all users) inputrc file /etc/inputrc# will be used. ##. If a user needs to modify the system's default inputrc configuration, he can change ~/.inputrc, which will overwrite the system's default configuration.

For information on how to edit the

inputrc file, run info bash and refer to the info page of bash #Readline Init FileIn this section, run info readline to reference readline's own info page. inputrc configuration

In the

inputrc

file, there are two configurations: one is the inputrc variable, and the other is the keyboard mapping. Note that when configuring this file, comments must occupy a separate line, otherwise problems may occur.

inputrc variable configuration

The syntax of variable configuration is as follows:

set variable value

Common variables and configuration are as follows:

completion-ignore-case
#如果设置为开(on)，在自动补全时不区分大小写。该配置默认是关。

show-all-if-ambiguous
#这个配置该变了自动补全函数的默认行为。如果设置为开(on)，当自动补全的结果有一个以上时，会直接列出这些结果。如果设置为关(off)，就会提示一个beep蜂鸣声，当再按下tab时才会列出自动补全的结果。默认这项配置为关。

bell-style
#Controls what happens when Readline wants to ring the terminal bell. If set to ‘none’, Readline never rings the bell. If set to ‘visible’, Readline uses a visible bell if one is available. If set to ‘audible’ (the default), Readline attempts to ring the terminal's bell.

bind-tty-special-chars
#If set to ‘on’, Readline attempts to bind the control characters treated specially by the kernel's terminal driver to their Readline equivalents.

comment-begin
#The string to insert at the beginning of the line when the insert-comment command is executed. The default value is "#".
completion-prefix-display-length

#When set to a value greater than zero, common prefixes longer than this value are replaced with an ellipsis when displaying possible completions.
#e.g. set completion-prefix-display-length 4

completion-query-items
#The number of possible completions that determines when the user is asked whether the list of possibilities should be displayed. If the number of possible completions is greater than this value, Readline will ask the user whether or not he wishes to view them; otherwise, they are simply listed. This variable must be set to an integer value greater than or equal to 0. A negative value means Readline should never ask. The default limit is 100.

convert-meta
#If set to ‘on’, Readline will convert characters with the eighth bit set to an ascii key sequence by stripping the eighth bit and prefixing an <ESC> character, converting them to a meta-prefixed key sequence. The default value is ‘on’.

disable-completion
#If set to ‘On’, Readline will inhibit word completion. Completion characters will be inserted into the line as if they had been mapped to self-insert. The default is ‘off’.

editing-mode
#The editing-mode variable controls which default set of key bindings is used. By default, Readline starts up in Emacs editing mode, where the keystrokes are most similar to Emacs. This variable can be set to either ‘emacs’ or ‘vi’.

echo-control-characters
#When set to ‘on’, on operating systems that indicate they support it, readline echoes a character corresponding to a signal generated from the keyboard. The default is ‘on’.

enable-keypad
#When set to ‘on’, Readline will try to enable the application keypad when it is called. Some systems need this to enable the arrow keys. The default is ‘off’.

enable-meta-key
#When set to ‘on’, Readline will try to enable any meta modifier key the terminal claims to support when it is called. On many terminals, the meta key is used to send eight-bit characters. The default is ‘on’.

expand-tilde
#If set to ‘on’, tilde expansion is performed when Readline attempts word completion. The default is ‘off’.

history-preserve-point
#If set to ‘on’, the history code attempts to place the point (the current cursor position) at the same location on each history line retrieved with previous-history or next-history. The default is ‘off’.

history-size
#Set the maximum number of history entries saved in the history list. If set to zero, the number of entries in the history list is not limited.

horizontal-scroll-mode
#This variable can be set to either ‘on’ or ‘off’. Setting it to ‘on’ means that the text of the lines being edited will scroll horizontally on a single screen line when they are longer than the width of the screen, instead of wrapping onto a new screen line. By default, this variable is set to ‘off’.

input-meta
#If set to ‘on’, Readline will enable eight-bit input (it will not clear the eighth bit in the characters it reads), regardless of what the terminal claims it can support. The default value is ‘off’. The name meta-flag is a synonym for this variable.

isearch-terminators
#The string of characters that should terminate an incremental search without subsequently executing the character as a command. If this variable has not been given a value, the characters <ESC> and C-J will terminate an incremental search.

keymap
#Sets Readline&#39;s idea of the current keymap for key binding commands. Acceptable keymap names are emacs, emacs-standard, emacs-meta, emacs-ctlx, vi, vi-move, vi-command, and vi-insert. vi is equivalent to vi-command; emacs is equivalent to emacs-standard. The default value is emacs. The value of the editing-mode variable also affects the default keymap.

mark-directories
#If set to ‘on’, completed directory names have a slash appended. The default is ‘on’.

mark-modified-lines
#This variable, when set to ‘on’, causes Readline to display an asterisk (*) at the start of history lines which have been modified. This variable is ‘off’ by default.

mark-symlinked-directories
#If set to ‘on’, completed names which are symbolic links to directories have a slash appended (subject to the value of mark-directories). The default is ‘off’.

match-hidden-files
#This variable, when set to ‘on’, causes Readline to match files whose names begin with a ‘.’ (hidden files) when performing filename completion, unless the leading ‘.’ is supplied by the user in the filename to be completed. This variable is ‘on’ by default.

output-meta
#If set to ‘on’, Readline will display characters with the eighth bit set directly rather than as a meta-prefixed escape sequence. The default is ‘off’.

page-completions
#If set to ‘on’, Readline uses an internal more-like pager to display a screenful of possible completions at a time. This variable is ‘on’ by default.

print-completions-horizontally
#If set to ‘on’, Readline will display completions with matches sorted horizontally in alphabetical order, rather than down the screen. The default is ‘off’.

revert-all-at-newline
If set to ‘on’, Readline will undo all changes to history lines before returning when accept-line is executed. By default, history lines can be modified and retain individual undo lists across calls to readline. The default is ‘off’.

show-all-if-unmodified
#This alters the default behavior of the completion functions in a fashion similar to show-all-if-ambiguous. If set to ‘on’, words which have more than one possible completion without any possible partial completion (the possible completions don&#39;t share a common prefix) cause the matches to be listed immediately instead of ringing the bell. The default value is ‘off’.

skip-completed-text
#If set to ‘on’, this alters the default completion behavior when inserting a single match into the line. It&#39;s only active when performing completion in the middle of a word. If enabled, readline does not insert characters from the completion that match characters after point in the word being completed, so portions of the word following the cursor are not duplicated. For instance, if this is enabled, attempting completion when the cursor is after the ‘e’ in ‘Makefile’ will result in ‘Makefile’ rather than ‘Makefilefile’, assuming there is a single possible completion. The default value is ‘off’.

visible-stats
#If set to ‘on’, a character denoting a file&#39;s type is appended to the filename when listing possible completions. The default is ‘off’.

Keymap configuration

Configuration

inputrc

The syntax of the variable is as follows: <pre class="brush:php;toolbar:false">keyname: function-name or macro #keyname必须是英文，可以是Control-u、Control-k等。并且keyname和冒号之间不能有空格，如果有空格会被认为是keyname的一部分。keyname的写法多样，取决于自己的喜好。 #下面是一些键盘映射配置的例子： Control-u: universal-argument C-u is bound to the function universal-argument Meta-Rubout: backward-kill-word M-DEL is bound to the function backward-kill-word Control-o: &quot;&gt; output&quot; C-o is bound to run the macro expressed on the right hand side (that is, to insert the text ‘&gt; output’ into the line) Control-j: menu-complete C-j is bound to cycle through the available tab completions. Control-k: menu-complete-backward C-k is bound to cycle backwards through the available tab completions. &quot;\t&quot;: menu-complete Use tab to cycle through all the possible completions. &quot;\C-p&quot;: history-search-backward Map control-p to allow search for completions to the current line from your history. e.g. type “git” and then hit control-p to cycle through all the recent git commands. &quot;\ep&quot;: history-search-backward Map escape-p to allow search for completions to the current line from your history. e.g. type “git” and then hit escape-p to cycle through all the recent git commands. &quot;\e[A&quot;: history-search-backward Map Up arrow to allow search for completions to the current line from your history. e.g. type “git” and then hit UP to cycle through all the recent git commands. &quot;\e[B&quot;: history-search-forward Map Down arrow to allow search for completions to the current line from your history. e.g. type “git” and then hit DOWN to cycle back through all the recent git commands. &quot;\C-d&quot;: kill-whole-line Map control-d to kill the whole line.</pre>

Set automatic completion under MacOS to be case-insensitive

Through the above introduction, it should be more than enough to solve this problem. Open the file

~/.inputrc in the user's home directory (

If it does not exist, create a new file), and add the following configuration to it: <pre class="brush:php;toolbar:false"># 设置自动补全不区分大小写 set completion-ignore-case on # 当有一个以上自动补全结果时，直接列出，不用beep提示 set show-all-if-ambiguous on</pre>Save the file, and then restart the command line , you will find that the auto-completion is not case-sensitive and has taken effect. Among many results on the Internet, you need to add the following configuration:

TAB: menu-complete

The purpose of this configuration is to list the auto-complete results and press the

tab

key again. Automatically select from the autocomplete list instead of always showing the autocomplete list. Recommended learning:

Mac OS introductory tutorial

, Linux video tutorial

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