read [-ers] [-u fd] [-t timeout] [-a aname] [-p prompt] [-n nchars] [-d delim] [name ...]
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. Options, if supplied, have the following meanings:
-a aname 将读取的内容放到数组aname中
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 以delim作为读取的内容的终结符
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 (see READLINE above) is used to obtain the line.
-n nchars 只读取n个字符
read returns after reading nchars characters rather than waiting for a complete line of input.
-p prompt 在读取任何内容之前，显示一个字符串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. 安静模式，不会将字符echo
If input is coming from a terminal, characters are not echoed.
-t timeout 指定超时时间
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 从文件读取得方法，当然要使用 fd
If no names are supplied, the line read is assigned to the ariable REPLY. The return code is zero, unless end-of-file is ncountered, read times out, or an invalid file descriptor is supplied as the argument to -u.
read -p "how old r u? " age
echo $age
read -p "some words? " -a words
echo ${words[*]}
read -p "Password: " -s passwd
echo $passwd
read -t 5 auth
echo $auth
read -n 1 key
read -dq -p "input something end with q: " menu
read -e file #在这试试命令历史和补齐功能
而且read a b c这样用也很实用:
echo -n "please year month day"
read a b c
echo $a $b $c
另外就是read读fd,比如常用的两个文件的拼接:
while read -u3 i && read -u4 j;do
echo $i $j
done 3
