shell 判断一个字符串是否由字母数字组成

 摘自：http://blog.51cto.com/lynnteng0/804520

?

1 2 3 4 5 6 7

describe="it's a describe by yourself"    if echo "$describe" | grep -q '^[a-zA-Z0-9]\+$'; then     echo "ok" else     echo "invalid" fi

　　

?

1 2 3 4 5

describe="it's a describe by yourself"    if echo "$describe" | grep -q '[^a-zA-Z0-9]'; then echo "invalid" fi