Question

需要帮助才能理解这个脚本我无法弄清楚-z条件对第一行的意义，然后在if语句中找出-z和"$1"的含义这是脚本：

while [ -z "$USERNAME" ]
do
if [ -z "$1" ]
    then
        unset ans
 unset USER
 echo "What is the username you would like to add?"
 read USER
 echo "Is" $USER " the correct username? [y/n]"
 read ans
 case "$ans" in
     y|Y|yes|Yes|YES)
  USERNAME=$USER

;;

Answer 1

-z
string is null, that is, has zero length

有关bash中Programming Languages Pragmatics的完整信息

有关$1。

的更多信息，请参阅test

Arguments passed to the script from the command line [1] : $0, $1, $2, $3 . . .

$0 is the name of the script itself, $1 is the first argument

Statement支持bash脚本

1 个答案: