Shell中统计字符串中单词的个数的几种方法

[linux@host ~]# echo 'one two three four five' | wc -w
5

[linux@host ~]# echo 'one two three four five' | awk '{print NF}'
5

[linux@host ~]# s='one two three four five' 
[linux@host ~]# set ${s}
[linux@host ~]# echo $#
5

[linux@host ~]# s='one two three four five' 
[linux@host ~]# a=($s)
[linux@host ~]# echo ${#a[@]}
5

[linux@host ~]# s='one two three four five' 
[linux@host ~]# echo $s | tr ' ' '\n' | wc -l
5