跟java里的split函数的用法是很相像的，举例如下：
The awk function split(s,a,sep) splits a string s into an awk array a using the delimiter sep.
set time = 12:34:56
set hr = `echo $time | awk '{split($0,a,":" ); print a[1]}'` # = 12
set sec = `echo $time | awk '{split($0,a,":" ); print a[3]}'` # = 56
# = 12 34 56
set hms = `echo $time | awk '{split($0,a,":" ); print a[1], a[2], a[3]}'`
set hms = `echo $time | awk '{split($0,a,":" ); for (i=1; i<=3; i++) print a[i]}'`
