Bash reference manual 5 (shell variable) continued 2

EMACS

If Bash finds that the value of this variable is 'T' in the environment when the shell is started, it considers that the shell runs in the Emacs shell Buffer and does not allow row editing.

ENV

Similar to BASH_ENV, it is used in shell in POSIX mode. (See Bash POSIX Mode)

EUID

Valid user ID in the digital format of the current user. This variable is read-only.

FCEDIT

The default editor when the built-in command fc has the-e option.

FIGNORE

A list of suffixes separated by colons. The content of this list is ignored when the execution file name is complete. When the suffix of a file name matches an element in FIGNORE, the file name is excluded from the list of matched file names. Example value: '. o :~ '.

FUNCNAME

Is an array variable that contains all the shell functions currently in the execution call stack. The element with index 0 is the name of any currently executed shell function. The bottommost (with the largest index) element is "main ". This variable exists only when the shell function is executed. Assigning a value to FUNCNAME has no effect and an error is returned. If FUNCNAME is unset, it loses its special attributes even if it is reset later.

This variable can be used together with BASH_LINENO and BASH_SOURCE. Each element of FUNCNAME corresponds to the content of BASH_LINENO and BASH_SOURCE to describe the call stack. For example, $ {FUNCNAME [$ I]} is called at $ {BASH_LINENO [$ I]} in the $ {BASH_SOURCE [$ I + 1]} file. The built-in caller command uses this information to display the current call stack.

Funnnst

If you set a number greater than 0, the maximum nested hierarchy of functions is defined. Function calls that exceed this value will cause the current command to stop running.

GLOBIGNORE

Is a colon-separated mode list that defines a collection of file names ignored during file name extension. If a file name matches the extension mode of the file name and also matches a pattern in GLOBIGNORE, it will be removed from the matching list.

GROUPS

Is an array variable that contains the list of groups to which the current user belongs. Assigning a value to GROUOS has no effect and an error is returned. If GROUPS is unset, it loses its special attributes even if it is subsequently reset.

Histchars

A maximum of 3 characters can be entered to control historical expansion, Fast replacement, and tagging (see historical interaction ). The first character is the historical extension character, marking the beginning of the historical extension, generally '! '. The second character marks a quick replacement-when it is the first character in a line, it is generally '^ '. The optional third character indicates that the rest of the line is a comment-when it is the first character of a word, it is generally '#'. The record of the record. It is not necessary because the shell interpreter will annotate the remaining parts.

HISTCMD

The number of the command history of the current command, or the index in the command history. If HISTCMD is unset, its special attributes are lost even if it is reset.

HISTCONTROL

A list of values separated by colons to control how commands are stored in the History list. If the list contains 'ignorespace', the command line starting with a space will not be stored in the command history. 'Ignooredups' causes the command lines that match the commands that have been stored in history to not be stored. 'Ignoreboth' is short for 'ignoredups' and 'ignorespace. 'Erasedups' causes the commands that match the command line in the history to be deleted before the command line is stored. All values not in the preceding list are ignored. If HISTCONTROL is unset or does not contain valid values, all command lines read by the shell interpreter are stored in the History list, except the values in HISTIGNORE. The second and subsequent lines of the multi-line command do not check, ignore the settings of HISTCONTROL, and add it to the command history.

HISTFILE

Name of the file that stores the command history. The default value is ~ /. Bash_history.

HISTFILESIZE

The maximum number of command lines in the history file. When this variable is assigned a value, if necessary, delete the oldest content in the history file so that the total number of rows does not exceed this value. In addition, when the Interactive shell exits, the content in the history file is also deleted, so as not to exceed this value. The default value is 500.

HISTIGNORE

The colon-separated mode list to determine which command line should be stored in the command history. Each mode starts with a line and must match the entire command line (without appending an implicit '*'). Each mode detection is performed after the HISTCONTROL test is completed. Except for the common shell pattern matching characters, '&' matches the previous command line. '&' Can be escaped using a backslash; remove the backslash before matching. The second and subsequent lines of the multi-line command do not check, ignore the settings of HISTIGNORE, and add it to the command history.

HISTIGNORE is a function that is classified into HISTCONTROL. The '&' mode is equivalent to 'ignoredups', while the '[] *' mode is equivalent to 'ignorespace '. Combine the two modes and separate them with a colon, that is, 'ignoreboth '.

HISTSIZE

The maximum number of commands that can be stored in the History list. The default value is 500.

HISTTIMEFORMAT

If the variable is set and is not empty, the value is used as the formatted string of strftime. It is used to print the timestamp for each historical content when calling the history built-in command. If this variable is set, the timestamp is written to the history file so that it can be kept between shell sessions. Use the history comment character to differentiate the timestamp and command line.

HOSTFILE

Contains the name of a file. The file is in the same format as/etc/hosts. When the shell completes a hostname, it reads information from the file. During shell running, the hostname Completion list may be changed. After the value is changed, Bash adds the content of the new file to the existing list in the next attempt to complete the hostname. If HOSTFILE is set but no value is specified, or it is not a readable file, Bash tries to read/etc/hosts to obtain the hostname Completion list. When HOSTFILE is unset, the hostname list is cleared.

HOSTNAME

The name of the current host.

HOSTTYPE

A string that describes the machine where Bash is running.

IGNOREEOF

Controls the shell action when an independent EOF character is entered. If this variable is set, the value of the variable indicates the number of consecutive EOF characters that can be read from the starting position in the input line before the shell exits. If the variable exists, but the value is not of the numeric type, or there is no value, the default value is 10. If this variable does not exist, the EOF indicates that the input to the shell ends. This variable is only valid in interactive shell.

INPUTRC

Readline initialization file name, overwrite the default ~ /. Inputrc.

LANG

It is used to determine the locale category of content specified by locale classification for variables that do not start with LC.

LC_ALL

This variable specifies the locale category, which overwrites the values of the variables starting with LANG and all other LC.

LC_COLLATE

This variable determines the sorting rules for file name extension results, and determines the behavior of the range expression, the equivalence class, and matching the sorting sequence and pattern of file name extension (see file name extension ).

LC_CTYPE

This variable determines the interpretation of characters and the behavior of character classes in file name extension and pattern matching (see file name extension ).

LC_MESSAGES

This variable determines the locale used to translate double quotation mark strings starting with '$. (See locale translation)

LC_NUMERIC

This variable determines the locale category of the number format.