如何在bash脚本中使用文件描述符3中的“读取”来读取？

http://bash.cyberciti.biz/file-management/shell-script-to-simulate-unix-more-command/如何在bash脚本中使用文件描述符3中的“读取”来读取？

#!/bin/bash 
# Write a shell script like a more command. It asks the user name, the 
# name of the file on command prompt and displays only the 15 lines of 
# the file at a time. 
# ------------------------------------------------------------------------- 
# Copyright (c) 2007 nixCraft project <http://cyberciti.biz/fb/> 
# This script is licensed under GNU GPL version 2.0 or above 
# ------------------------------------------------------------------------- 
# This script is part of nixCraft shell script collection (NSSC) 
# Visit http://bash.cyberciti.biz/ for more information. 
# ------------------------------------------------------------------------- 

counter=1 
echo -n "Enter a file name : " 
read file 

if [ ! -f $file ] 
then 
    echo "$file not a file!" 
    exit 1 
fi 

# read file line by line 
exec 3<&0 
while read line 
do 
     # pause at line no. 15 
    if [ $counter -eq 15 ] 
    then 
     counter=0 # reset counter 
     echo " *** Press [Enter] key to continue ..." 
     read -u 3 enterKey 
    fi 
    echo $line 
    ((counter++)) 
done < $file

这模拟多个命令.. 我得到这个错误..

读：26：-u

非法选项确保输入的名称一个文件有超过15行.. 此外我读了“阅读”的手册页，我没有得到像“-u”的选项..

那么，我如何阅读使用“读取”从文件描述符3（这是stdin的副本）。

来源

2010-01-18 Abhijeet Rastogi

什么的Bash版本：接下来的空闲描述符数量将从10 例如开始进行分配？ – 2010-01-18 16:18:40

尝试

read key <&3

来源

2010-01-18 15:48:04 ghostdog74

：omg：那很容易。 thanx .. – 2010-01-18 15:51:53

我得到：'-bash：3：Bad file descriptor' – Timo 2018-03-02 06:58:30

只是为了记录在案，这里的又一多个脚本：

# Author: Steve Stock 
# http://www.linuxjournal.com/article/7385 (comments) 

shmore() { 
LINES="" 
while read -d $'\n' line; do 
    printf "%s\n" "$line" 
    #echo "$line" 
    LINES=".${LINES}" 
    if [[ "$LINES" == "......................." ]]; then 
    echo -n "--More--" 
    read < /dev/tty 
    LINES="" 
    fi 
done 
return 0 
} 


shmore < file.txt

这里找到：http://codesnippets.joyent.com/posts/show/1788

来源

2010-01-18 19:41:16 mirro

也有可能得到的bash的文件描述符分配给一个变量;

#!/bin/bash 
FILENAME="my_file.txt" 
exec {FD}<${FILENAME}  # open file for read, assign descriptor 
echo "Opened ${FILENAME} for read using descriptor ${FD}" 
while read -u ${FD} LINE 
do 
    # do something with ${LINE} 
    echo ${LINE} 
done 
exec {FD}<&- # close file

来源

2015-02-03 14:04:15

如何在bash脚本中使用文件描述符3中的“读取”来读取？

回答

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