一 字符串判断
二 实战
[[email protected] ~]# name=fengji
[[email protected] ~]# [ -z $name ] && echo yes || echo no
no
[[email protected] ~]# name=""
[[email protected] ~]# [ -z $name ] && echo yes || echo no
yes
[[email protected] ~]# aa=11
[[email protected] ~]# bb=22
[[email protected] ~]# [ "$aa" == "$bb" ] && echo yes || echo no
no
[[email protected] ~]# [ "$aa" -eq "$bb" ] && echo yes || echo no
no
[[email protected] ~]# aa=22
[[email protected] ~]# [ "$aa" -eq "$bb" ] && echo yes || echo no
yes
[[email protected] ~]# [ "$aa" == "$bb" ] && echo yes || echo no
yes
三 多重条件判断
四 实战
[[email protected] ~]# aa=22
[[email protected] ~]# [ -n "$aa" -a "$aa" -gt 33 ] && echo yes || echo no
no
[[email protected] ~]# [ -n "$aa" -a "$aa" -gt 3 ] && echo yes || echo no
yes