Read one line from the standard input, (or from a file) and assign the word(s) to variable name(s).
Syntax
read [-ers] [-u fd] [-t timeout] [-a aname] [-p prompt]
[-n nchars] [-d delim] [name ...]
Key
-a aname
The words are assigned to sequential indices of the array variable aname, starting at 0.
aname is unset before any new values are assigned. Other name arguments are ignored.
-d delim
The first character of delim is used to terminate the input line, rather than newline.
-e If the standard input is coming from a terminal, readline is used to obtain the line.
-n nchars
read returns after reading nchars characters rather than waiting for a complete line of
input.
-p prompt
Display prompt on standard error, without a trailing newline, before attempting to read
any input. The prompt is displayed only if input is coming from a terminal.
-r 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 is not read
within timeout seconds. This option has no effect if read is not reading input from
the terminal or a pipe.
-u fd Read input from file descriptor fd.
One line is read from the standard input, or from the file descriptor fd supplied as an argument to the -u option, and the first word is assigned to the first name, the second word to the second name, and so on, with leftover words and their intervening separators assigned to the last name.
If there are fewer words read from the input stream than names, the remaining names are assigned empty values. The characters in IFS are used to split the line into words. The backslash character (\) may be used to remove any special meaning for the next character read and for line continuation.
If no names are supplied, the line read is assigned to the variable REPLY.
The return code is zero, unless end-of-file is encountered, read times out, or an invalid file descriptor is supplied as the argument to -u.
read is a bash builtin command.
Related:
expr - Evaluate expressions
