Shell中Read用法简介

一.  read读取单个词. $read name
$tony ma
$echo $name
tony ma

$read id passwd
$allen passwd
$echo $id
$allen
$echo $passwd
$passwd

$read id passwd
$allen kaka gogo
$echo $id
$allen
$echo $passwd
$kaka gogo 二.  read读取整行.      利用while循环来使read读取整行。      以下是代码清单： 1  #!/bin/bash
2  lineno=13  cat $* |4  while read -r line
5  do
6          echo "$lineno: $line"
7          lineno=$((lineno + 1))
8  done 三.   read的嵌套.       1）while外层的read依次读取的是文件pbook中的每一行，而内层的read是从console读取的内容。      2）要实现while read的嵌套，可以使用exec命令，将I/O重定向。        注意exec的用法，以及括号的使用。  1  #!/bin/bash
2  echo -n "Enter name to be removed: "
3  read name
4  p=$(grep "$name " phonebook | wc -l)
5  echo $p
6  if [ "$p" -gt 1 ]
7  then
8          echo "More than one match ; Please select the one to remove;"
9          grep  "$name " phonebook > pbook
10          cat pbook | while read line
11          do (
12                echo -n  "$line  Remove(y/n)?"
13                exec < /dev/tty
14                read answer
15                if [ "$answer" = y ]
16                then
17                          grep -v "^$line$" phonebook > /tmp/phonebook.tmp
18                          mv /tmp/phonebook.tmp phonebook
19                else
20                          continue
21                fi22             )
23          done
24  else
25          grep -v "^$line$" phonebook > /tmp/phonebook.tmp
26          mv /tmp/phonebook.tmp phonebook27  fi28  cat phonebook