Advanced Bash Scripting Guide 7-10

directory=${1-`pwd`} #如果没有设置参数，则默认置为当前目录

for a #没有指明列表，则默认使用$@

for planet in "Mercury 36" "Venus 67" "Earth 93" "Mars 142" "Jupiter 483" 
do 
set -- $planet # 解析$planet到$@,比如"Mercury 36"就分成"Mercury", "36" 
echo "$1 $2,000,000 miles from the sun" 
done

for a in {1..10} # 从1到10的序列 
do 
echo -n "$a " 
done

#命令行参数处理，case 
while [ $# -gt 0 ]; do # Until you run out of parameters . . . 
case "$1" in 
-d|--debug) 
# "-d" or "--debug" parameter? 
DEBUG=1 
;; 
-c|--conf) 
CONFFILE="$2" 
shift 
if [ ! -f $CONFFILE ]; then 
echo "Error: Supplied file doesn't exist!" 
exit $E_CONFFILE # File not found error. 
fi 
;; 
esac 
shift # Check next set of parameters. 
done