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

describe="it's a describe by yourself"

if echo "$describe" | grep -q '^[a-zA-Z0-9]\+$'; then

    echo "ok"

else

    echo "invalid"

fi

　　

describe="it's a describe by yourself"

if echo "$describe" | grep -q '[^a-zA-Z0-9]'; then

echo "invalid"

fi