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   sh.1p    ( 1 )

оболочка, стандартный интерпретатор командного языка (shell, the standard command language interpreter)

Расширенное описание (Extended description)

See Chapter 2, Shell Command Language.  The functionality
       described in the rest of the EXTENDED DESCRIPTION section shall
       be provided on implementations that support the User Portability
       Utilities option (and the rest of this section is not further
       shaded for this option).

Command History List When the sh utility is being used interactively, it shall maintain a list of commands previously entered from the terminal in the file named by the HISTFILE environment variable. The type, size, and internal format of this file are unspecified. Multiple sh processes can share access to the file for a user, if file access permissions allow this; see the description of the HISTFILE environment variable.

Command Line Editing When sh is being used interactively from a terminal, the current command and the command history (see fc(1p)) can be edited using vi-mode command line editing. This mode uses commands, described below, similar to a subset of those described in the vi utility. Implementations may offer other command line editing modes corresponding to other editing utilities.

The command set -o vi shall enable vi-mode editing and place sh into vi insert mode (see Command Line Editing (vi-mode)). This command also shall disable any other editing mode that the implementation may provide. The command set +o vi disables vi- mode editing.

Certain block-mode terminals may be unable to support shell command line editing. If a terminal is unable to provide either edit mode, it need not be possible to set -o vi when using the shell on this terminal.

In the following sections, the characters erase, interrupt, kill, and end-of-file are those set by the stty utility.

Command Line Editing (vi-mode) In vi editing mode, there shall be a distinguished line, the edit line. All the editing operations which modify a line affect the edit line. The edit line is always the newest line in the command history buffer.

With vi-mode enabled, sh can be switched between insert mode and command mode.

When in insert mode, an entered character shall be inserted into the command line, except as noted in vi Line Editing Insert Mode. Upon entering sh and after termination of the previous command, sh shall be in insert mode.

Typing an escape character shall switch sh into command mode (see vi Line Editing Command Mode). In command mode, an entered character shall either invoke a defined operation, be used as part of a multi-character operation, or be treated as an error. A character that is not recognized as part of an editing command shall terminate any specific editing command and shall alert the terminal. If sh receives a SIGINT signal in command mode (whether generated by typing the interrupt character or by other means), it shall terminate command line editing on the current command line, reissue the prompt on the next line of the terminal, and reset the command history (see fc(1p)) so that the most recently executed command is the previous command (that is, the command that was being edited when it was interrupted is not re-entered into the history).

In the following sections, the phrase ``move the cursor to the beginning of the word'' shall mean ``move the cursor to the first character of the current word'' and the phrase ``move the cursor to the end of the word'' shall mean ``move the cursor to the last character of the current word''. The phrase ``beginning of the command line'' indicates the point between the end of the prompt string issued by the shell (or the beginning of the terminal line, if there is no prompt string) and the first character of the command text.

vi Line Editing Insert Mode While in insert mode, any character typed shall be inserted in the current command line, unless it is from the following set.

<newline> Execute the current command line. If the current command line is not empty, this line shall be entered into the command history (see fc(1p)).

erase Delete the character previous to the current cursor position and move the current cursor position back one character. In insert mode, characters shall be erased from both the screen and the buffer when backspacing.

interrupt If sh receives a SIGINT signal in insert mode (whether generated by typing the interrupt character or by other means), it shall terminate command line editing with the same effects as described for interrupting command mode; see Command Line Editing (vi-mode).

kill Clear all the characters from the input line.

<control>‐V Insert the next character input, even if the character is otherwise a special insert mode character.

<control>‐W Delete the characters from the one preceding the cursor to the preceding word boundary. The word boundary in this case is the closer to the cursor of either the beginning of the line or a character that is in neither the blank nor punct character classification of the current locale.

end-of-file Interpreted as the end of input in sh. This interpretation shall occur only at the beginning of an input line. If end-of-file is entered other than at the beginning of the line, the results are unspecified.

<ESC> Place sh into command mode.

vi Line Editing Command Mode In command mode for the command line editing feature, decimal digits not beginning with 0 that precede a command letter shall be remembered. Some commands use these decimal digits as a count number that affects the operation.

The term motion command represents one of the commands:

<space> 0 b F l W ^ $ ; E f T w | , B e h t

If the current line is not the edit line, any command that modifies the current line shall cause the content of the current line to replace the content of the edit line, and the current line shall become the edit line. This replacement cannot be undone (see the u and U commands below). The modification requested shall then be performed to the edit line. When the current line is the edit line, the modification shall be done directly to the edit line.

Any command that is preceded by count shall take a count (the numeric value of any preceding decimal digits). Unless otherwise noted, this count shall cause the specified operation to repeat by the number of times specified by the count. Also unless otherwise noted, a count that is out of range is considered an error condition and shall alert the terminal, but neither the cursor position, nor the command line, shall change.

The terms word and bigword are used as defined in the vi description. The term save buffer corresponds to the term unnamed buffer in vi.

The following commands shall be recognized in command mode:

<newline> Execute the current command line. If the current command line is not empty, this line shall be entered into the command history (see fc(1p)).

<control>‐L Redraw the current command line. Position the cursor at the same location on the redrawn line.

# Insert the character '#' at the beginning of the current command line and treat the resulting edit line as a comment. This line shall be entered into the command history; see fc(1p).

= Display the possible shell word expansions (see Section 2.6, Word Expansions) of the bigword at the current command line position.

Note: This does not modify the content of the current line, and therefore does not cause the current line to become the edit line.

These expansions shall be displayed on subsequent terminal lines. If the bigword contains none of the characters '?', '*', or '[', an <asterisk> ('*') shall be implicitly assumed at the end. If any directories are matched, these expansions shall have a '/' character appended. After the expansion, the line shall be redrawn, the cursor repositioned at the current cursor position, and sh shall be placed in command mode.

\ Perform pathname expansion (see Section 2.6.6, Pathname Expansion) on the current bigword, up to the largest set of characters that can be matched uniquely. If the bigword contains none of the characters '?', '*', or '[', an <asterisk> ('*') shall be implicitly assumed at the end. This maximal expansion then shall replace the original bigword in the command line, and the cursor shall be placed after this expansion. If the resulting bigword completely and uniquely matches a directory, a '/' character shall be inserted directly after the bigword. If some other file is completely matched, a single <space> shall be inserted after the bigword. After this operation, sh shall be placed in insert mode.

* Perform pathname expansion on the current bigword and insert all expansions into the command to replace the current bigword, with each expansion separated by a single <space>. If at the end of the line, the current cursor position shall be moved to the first column position following the expansions and sh shall be placed in insert mode. Otherwise, the current cursor position shall be the last column position of the first character after the expansions and sh shall be placed in insert mode. If the current bigword contains none of the characters '?', '*', or '[', before the operation, an <asterisk> ('*') shall be implicitly assumed at the end.

@letter Insert the value of the alias named _letter. The symbol letter represents a single alphabetic character from the portable character set; implementations may support additional characters as an extension. If the alias _letter contains other editing commands, these commands shall be performed as part of the insertion. If no alias _letter is enabled, this command shall have no effect.

[count]~ Convert, if the current character is a lowercase letter, to the equivalent uppercase letter and vice versa, as prescribed by the current locale. The current cursor position then shall be advanced by one character. If the cursor was positioned on the last character of the line, the case conversion shall occur, but the cursor shall not advance. If the '~' command is preceded by a count, that number of characters shall be converted, and the cursor shall be advanced to the character position after the last character converted. If the count is larger than the number of characters after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]. Repeat the most recent non-motion command, even if it was executed on an earlier command line. If the previous command was preceded by a count, and no count is given on the '.' command, the count from the previous command shall be included as part of the repeated command. If the '.' command is preceded by a count, this shall override any count argument to the previous command. The count specified in the '.' command shall become the count for subsequent '.' commands issued without a count.

[number]v Invoke the vi editor to edit the current command line in a temporary file. When the editor exits, the commands in the temporary file shall be executed and placed in the command history. If a number is included, it specifies the command number in the command history to be edited, rather than the current command line.

[count]l (ell)

[count]<space> Move the current cursor position to the next character position. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the count is larger than the number of characters after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]h Move the current cursor position to the countth (default 1) previous character position. If the cursor was positioned on the first character of the line, the terminal shall be alerted and the cursor shall not be moved. If the count is larger than the number of characters before the cursor, this shall not be considered an error; the cursor shall move to the first character on the line.

[count]w Move to the start of the next word. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the count is larger than the number of words after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]W Move to the start of the next bigword. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the count is larger than the number of bigwords after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]e Move to the end of the current word. If at the end of a word, move to the end of the next word. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the count is larger than the number of words after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]E Move to the end of the current bigword. If at the end of a bigword, move to the end of the next bigword. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the count is larger than the number of bigwords after the cursor, this shall not be considered an error; the cursor shall advance to the last character on the line.

[count]b Move to the beginning of the current word. If at the beginning of a word, move to the beginning of the previous word. If the cursor was positioned on the first character of the line, the terminal shall be alerted and the cursor shall not be moved. If the count is larger than the number of words preceding the cursor, this shall not be considered an error; the cursor shall return to the first character on the line.

[count]B Move to the beginning of the current bigword. If at the beginning of a bigword, move to the beginning of the previous bigword. If the cursor was positioned on the first character of the line, the terminal shall be alerted and the cursor shall not be moved. If the count is larger than the number of bigwords preceding the cursor, this shall not be considered an error; the cursor shall return to the first character on the line.

^ Move the current cursor position to the first character on the input line that is not a <blank>.

$ Move to the last character position on the current command line.

0 (Zero.) Move to the first character position on the current command line.

[count]| Move to the countth character position on the current command line. If no number is specified, move to the first position. The first character position shall be numbered 1. If the count is larger than the number of characters on the line, this shall not be considered an error; the cursor shall be placed on the last character on the line.

[count]fc Move to the first occurrence of the character 'c' that occurs after the current cursor position. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the character 'c' does not occur in the line after the current cursor position, the terminal shall be alerted and the cursor shall not be moved.

[count]Fc Move to the first occurrence of the character 'c' that occurs before the current cursor position. If the cursor was positioned on the first character of the line, the terminal shall be alerted and the cursor shall not be moved. If the character 'c' does not occur in the line before the current cursor position, the terminal shall be alerted and the cursor shall not be moved.

[count]tc Move to the character before the first occurrence of the character 'c' that occurs after the current cursor position. If the cursor was positioned on the last character of the line, the terminal shall be alerted and the cursor shall not be advanced. If the character 'c' does not occur in the line after the current cursor position, the terminal shall be alerted and the cursor shall not be moved.

[count]Tc Move to the character after the first occurrence of the character 'c' that occurs before the current cursor position. If the cursor was positioned on the first character of the line, the terminal shall be alerted and the cursor shall not be moved. If the character 'c' does not occur in the line before the current cursor position, the terminal shall be alerted and the cursor shall not be moved.

[count]; Repeat the most recent f, F, t, or T command. Any number argument on that previous command shall be ignored. Errors are those described for the repeated command.

[count], Repeat the most recent f, F, t, or T command. Any number argument on that previous command shall be ignored. However, reverse the direction of that command.

a Enter insert mode after the current cursor position. Characters that are entered shall be inserted before the next character.

A Enter insert mode after the end of the current command line.

i Enter insert mode at the current cursor position. Characters that are entered shall be inserted before the current character.

I Enter insert mode at the beginning of the current command line.

R Enter insert mode, replacing characters from the command line beginning at the current cursor position.

[count]cmotion Delete the characters between the current cursor position and the cursor position that would result from the specified motion command. Then enter insert mode before the first character following any deleted characters. If count is specified, it shall be applied to the motion command. A count shall be ignored for the following motion commands:

0 ^ $ c

If the motion command is the character 'c', the current command line shall be cleared and insert mode shall be entered. If the motion command would move the current cursor position toward the beginning of the command line, the character under the current cursor position shall not be deleted. If the motion command would move the current cursor position toward the end of the command line, the character under the current cursor position shall be deleted. If the count is larger than the number of characters between the current cursor position and the end of the command line toward which the motion command would move the cursor, this shall not be considered an error; all of the remaining characters in the aforementioned range shall be deleted and insert mode shall be entered. If the motion command is invalid, the terminal shall be alerted, the cursor shall not be moved, and no text shall be deleted.

C Delete from the current character to the end of the line and enter insert mode at the new end-of-line.

S Clear the entire edit line and enter insert mode.

[count]rc Replace the current character with the character 'c'. With a number count, replace the current and the following count-1 characters. After this command, the current cursor position shall be on the last character that was changed. If the count is larger than the number of characters after the cursor, this shall not be considered an error; all of the remaining characters shall be changed.

[count]_ Append a <space> after the current character position and then append the last bigword in the previous input line after the <space>. Then enter insert mode after the last character just appended. With a number count, append the countth bigword in the previous line.

[count]x Delete the character at the current cursor position and place the deleted characters in the save buffer. If the cursor was positioned on the last character of the line, the character shall be deleted and the cursor position shall be moved to the previous character (the new last character). If the count is larger than the number of characters after the cursor, this shall not be considered an error; all the characters from the cursor to the end of the line shall be deleted.

[count]X Delete the character before the current cursor position and place the deleted characters in the save buffer. The character under the current cursor position shall not change. If the cursor was positioned on the first character of the line, the terminal shall be alerted, and the X command shall have no effect. If the line contained a single character, the X command shall have no effect. If the line contained no characters, the terminal shall be alerted and the cursor shall not be moved. If the count is larger than the number of characters before the cursor, this shall not be considered an error; all the characters from before the cursor to the beginning of the line shall be deleted.

[count]dmotion Delete the characters between the current cursor position and the character position that would result from the motion command. A number count repeats the motion command count times. If the motion command would move toward the beginning of the command line, the character under the current cursor position shall not be deleted. If the motion command is d, the entire current command line shall be cleared. If the count is larger than the number of characters between the current cursor position and the end of the command line toward which the motion command would move the cursor, this shall not be considered an error; all of the remaining characters in the aforementioned range shall be deleted. The deleted characters shall be placed in the save buffer.

D Delete all characters from the current cursor position to the end of the line. The deleted characters shall be placed in the save buffer.

[count]ymotion Yank (that is, copy) the characters from the current cursor position to the position resulting from the motion command into the save buffer. A number count shall be applied to the motion command. If the motion command would move toward the beginning of the command line, the character under the current cursor position shall not be included in the set of yanked characters. If the motion command is y, the entire current command line shall be yanked into the save buffer. The current cursor position shall be unchanged. If the count is larger than the number of characters between the current cursor position and the end of the command line toward which the motion command would move the cursor, this shall not be considered an error; all of the remaining characters in the aforementioned range shall be yanked.

Y Yank the characters from the current cursor position to the end of the line into the save buffer. The current character position shall be unchanged.

[count]p Put a copy of the current contents of the save buffer after the current cursor position. The current cursor position shall be advanced to the last character put from the save buffer. A count shall indicate how many copies of the save buffer shall be put.

[count]P Put a copy of the current contents of the save buffer before the current cursor position. The current cursor position shall be moved to the last character put from the save buffer. A count shall indicate how many copies of the save buffer shall be put.

u Undo the last command that changed the edit line. This operation shall not undo the copy of any command line to the edit line.

U Undo all changes made to the edit line. This operation shall not undo the copy of any command line to the edit line.

[count]k

[count]- Set the current command line to be the countth previous command line in the shell command history. If count is not specified, it shall default to 1. The cursor shall be positioned on the first character of the new command. If a k or - command would retreat past the maximum number of commands in effect for this shell (affected by the HISTSIZE environment variable), the terminal shall be alerted, and the command shall have no effect.

[count]j

[count]+ Set the current command line to be the countth next command line in the shell command history. If count is not specified, it shall default to 1. The cursor shall be positioned on the first character of the new command. If a j or + command advances past the edit line, the current command line shall be restored to the edit line and the terminal shall be alerted.

[number]G Set the current command line to be the oldest command line stored in the shell command history. With a number number, set the current command line to be the command line number in the history. If command line number does not exist, the terminal shall be alerted and the command line shall not be changed.

/pattern<newline> Move backwards through the command history, searching for the specified pattern, beginning with the previous command line. Patterns use the pattern matching notation described in Section 2.13, Pattern Matching Notation, except that the '^' character shall have special meaning when it appears as the first character of pattern. In this case, the '^' is discarded and the characters after the '^' shall be matched only at the beginning of a line. Commands in the command history shall be treated as strings, not as filenames. If the pattern is not found, the current command line shall be unchanged and the terminal shall be alerted. If it is found in a previous line, the current command line shall be set to that line and the cursor shall be set to the first character of the new command line.

If pattern is empty, the last non-empty pattern provided to / or ? shall be used. If there is no previous non-empty pattern, the terminal shall be alerted and the current command line shall remain unchanged.

?pattern<newline> Move forwards through the command history, searching for the specified pattern, beginning with the next command line. Patterns use the pattern matching notation described in Section 2.13, Pattern Matching Notation, except that the '^' character shall have special meaning when it appears as the first character of pattern. In this case, the '^' is discarded and the characters after the '^' shall be matched only at the beginning of a line. Commands in the command history shall be treated as strings, not as filenames. If the pattern is not found, the current command line shall be unchanged and the terminal shall be alerted. If it is found in a following line, the current command line shall be set to that line and the cursor shall be set to the fist character of the new command line.

If pattern is empty, the last non-empty pattern provided to / or ? shall be used. If there is no previous non-empty pattern, the terminal shall be alerted and the current command line shall remain unchanged.

n Repeat the most recent / or ? command. If there is no previous / or ?, the terminal shall be alerted and the current command line shall remain unchanged.

N Repeat the most recent / or ? command, reversing the direction of the search. If there is no previous / or ?, the terminal shall be alerted and the current command line shall remain unchanged.