ex28.sh

BASH Shell 编程 经典教程 《高级SHELL脚本编程》中文版

#!/bin/bash

LIMIT=19  # 上限

echo
echo "Printing Numbers 1 through 20 (but not 3 and 11)."

a=0

while [ $a -le "$LIMIT" ]
do
 a=$(($a+1))

 if [ "$a" -eq 3 ] || [ "$a" -eq 11 ]  # 除了3和11.
 then
   continue      # 跳过本次循环剩余的语句.
 fi

 echo -n "$a "   # 在$a等于3和11的时候，这句将不会执行.
done 

# 练习:
# 为什么循环会打印出20?

echo; echo

echo Printing Numbers 1 through 20, but something happens after 2.

##################################################################

# 同样的循环, 但是用'break'来代替'continue'.

a=0

while [ "$a" -le "$LIMIT" ]
do
 a=$(($a+1))

 if [ "$a" -gt 2 ]
 then
   break  # 将会跳出整个循环.
 fi

 echo -n "$a "
done

echo; echo; echo

exit 0