bash 如何在bash脚本中使用“读取”从文件描述符3中读取？
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How to read using "read" from file descriptor 3 in bash script?
提问by Abhijeet Rastogi
http://bash.cyberciti.biz/file-management/shell-script-to-simulate-unix-more-command/
http://bash.cyberciti.biz/file-management/shell-script-to-simulate-unix-more-command/
#!/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 < $file
This emulates more command.. I get this error..
这模拟了更多命令..我收到这个错误..
read: 26: Illegal option -u
阅读：26：非法选项 -u
Make sure to enter the name of a file which has more than 15 lines.. Also I read the man page of "read" and i didnt get an option like "-u"..
确保输入超过 15 行的文件名。我还阅读了“read”的手册页，但没有得到“-u”之类的选项。
So, how do i read using "read" from the file descriptor 3 (which is copy of stdin).
那么，我如何使用文件描述符 3（这是标准输入的副本）中的“读取”进行读取。
回答by ghostdog74
try
尝试
read key <&3
回答by Ed Randall
It's also possible to get bash to assign a file descriptor to a variable; The next free descriptor number will be allocated starting from 10. For example:
也可以让 bash 将文件描述符分配给变量；下一个空闲描述符编号将从 10 开始分配。例如：
#!/bin/bash
FILENAME="my_file.txt"
exec {FD}<${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
回答by mirro
Just for the record, here's yet another more script:
只是为了记录，这里还有另一个脚本：
# 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
found here: http://codesnippets.joyent.com/posts/show/1788
