转载－shell函数应用实例介绍

原文地址：http://blog.chinaunix.net/u/4206/showart.php?id=654250

代码:
$cat dbfunctions
addon () { # 定义函数addon,他的功能是把新的信息加入datafile
while true
do
echo "Adding information "
echo "Type the full name of employee "
read name
echo "Type address for employee "
read address
echo "Type start date for employee (4/10/88 ) :"
read startdate
echo $name:$address:$startdate
echo -n "Is this correct? "
read ans
case "$ans" in
[Yy]*)
echo "Adding info..."
echo $name:$address:$startdate>>datafile
sort -u datafile -o datafile
echo -n "Do you want to go back to the main menu? "
read ans
if [ $ans = Y -o $ans = y ]
then
return # return命令把控制送回函数被调用时所在的调用程序
else
continue # 把控制返回到while循环顶部
fi
;;
*)
echo "Do you want to try again? "
read answer
case "$answer" in
[Yy]*)
continue;;
*)
exit;;
esac
;;
esac
done
} # 结束函数定义

$cat mainprog
#!/bin/sh
script. name: mainprog
# This is the main script. that will call the function, addon

#datafile=$HOME/bourne/datafile
datafile=./datafile

. dbfunctions # dot命令把文件dbfunctions装入内存,

if [ ! -f $datafile ]
then
echo "`basename $datafile` does not exist" 1>&2
exit 1
fi
echo "Select one: "
cat <<EOF
[1] Add info
[2] Delete info
[3] Exit
EOF
read choice
case $choice in
1) addon # 调用函数
;;
2) delete # 调用函数
;;
3) update
;;
4) echo Bye
exit 0
;;
*) echo Bad choice
exit 2
;;
esac
echo Returned from function call
echo The name is $name
# Variable set in the function are known in this shell.

附:文件datafile
cat database
Ann Stephens 111 Main St, Boston, MA 4/10/88
TB Savage 222 B Ave, New York, NY 5/11/99