SHELL脚本编程循环篇-for循环

　　　　　　　　　　　　　　SHELL脚本编程循环篇-for循环

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　作者：尹正杰

版权声明：原创作品，谢绝转载！否则将追究法律责任。

 

 

 

 

一.for循环的语法格式

[root@node101.yinzhengjie.org.cn ~]# help for
for: for NAME [in WORDS ... ] ; do COMMANDS; done
    Execute commands for each member in a list.
    
    The `for' loop executes a sequence of commands for each member in a
    list of items.  If `in WORDS ...;' is not present, then `in "$@"' is
    assumed.  For each element in WORDS, NAME is set to that element, and
    the COMMANDS are executed.
    
    Exit Status:
    Returns the status of the last command executed.
for ((: for (( exp1; exp2; exp3 )); do COMMANDS; done
    Arithmetic for loop.
    
    Equivalent to
        (( EXP1 ))
        while (( EXP2 )); do
            COMMANDS
            (( EXP3 ))
        done
    EXP1, EXP2, and EXP3 are arithmetic expressions.  If any expression is
    omitted, it behaves as if it evaluates to 1.
    
    Exit Status:
    Returns the status of the last command executed.
[root@node101.yinzhengjie.org.cn ~]# 
[root@node101.yinzhengjie.org.cn ~]# 

[root@node101.yinzhengjie.org.cn ~]# help for