Shell 递归程序设计-目录列表

Shell 递归程序设计-目录列表
本文出自: http://ehnt.net/clansoft/gb/ (2001-06-18 11:00:00)
��UNIX Shell 脚本类似 DOS 的批处理命令，但比较起来 UNIX Shell 的功能更强大，在某些方面，Shell 甚至超过了一些高级语言。
��下边的 Shell 脚本演示了如何用 Shell 脚本编写递归程序。

��运行前先执行下述准备命令：
��ln tree.sh /usr/bin/tree
��ln tree.sh /usr/bin/wtree
��ln tree.sh /usr/bin/dtree
��rm tree.sh

# tree.sh

# Depth first Directory list
dtree() { 
PWD=`pwd|sed 's/\/\$//`
for d in $*
do
echo "${PWD}/$d"
[ -d "$d" -a -x "$d" ] && {
        cd "$d"
        dtree *
        cd ..
        PWD=`pwd|sed 's/\/\$//` # restore PWD
        }
done
} 

# Depth first Directory list
wtree() {        
PWD=`pwd|sed 's/\/\$//`
for d in $*
do
        echo ${PWD}/$d        
done
for d in $*
do
        [ -d "$d" -a -x "$d" ] && {
        cd $d
        wtree *
        cd ..
        }
done
}

# Directory list
tree() {        
PWD=`pwd|sed 's/\/\$//`
for d in $*
do
        echo ${PWD}/$d        
done
}

# main
TREE=`basename $0`
if [ "$1" ]
then DIR="$1"
else DIR="."
fi
if cd $DIR
then $TREE *
else echo "$0: Directory $1 read fail."
fi

# (End)