Chapter 4: Shell Builtin Commands

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-n nchars read returns after reading nchars characters rather than waiting for a complete line of input, but honor a delimiter if fewer than nchars characters are read before the delimiter.

-N nchars read returns after reading exactly nchars characters rather than waiting for a complete line of input, unless EOF is encountered or read times out. Delimiter characters encountered in the input are not treated specially and do not cause read to return until nchars characters are read.

-p prompt Display prompt, without a trailing newline, before attempting to read any input. The prompt is displayed only if input is coming from a terminal.

-r

If this option is given, backslash does not act as an escape character.

The backslash is considered to be part of the line. In particular, a backslash-newline pair may not be used as a line continuation.

-s

Silent mode. If input is coming from a terminal, characters are not echoed.

-t timeout

Cause read to time out and return failure if a complete line of input (or a specified number of characters) is not read within time- out seconds. timeout may be a decimal number with a fractional portion following the decimal point. This option is only effective if read is reading input from a terminal, pipe, or other special file; it has no effect when reading from regular files. If read times out, read saves any partial input read into the specified variable name.

If timeout is 0, read returns immediately, without trying to read and data. The exit status is 0 if input is available on the specified file descriptor, non-zero otherwise. The exit status is greater than

128 if the timeout is exceeded.

-u fd

Read input from file descriptor fd. readarray readarray [-n count] [-O origin] [-s count] [-t] [-u fd]

[-C callback] [-c quantum] [array]

Read lines from the standard input into the indexed array variable array, or from file descriptor fd if the -u option is supplied.

A synonym for mapfile. source source filename

A synonym for . (see Section 4.1 [Bourne Shell Builtins], page 41). type type [-afptP] [name ...]

For each name, indicate how it would be interpreted if used as a command name.