Writing shell Scripts--judging the user's parameters

Test statement format: [conditional expression]

A few common forms:

[-D/ETC] to determine if/etc is a directory type,

[-e/etc/php.ini] Determine if the/etc/php.ini file exists

[-f/etc/php.ini] Judge/etc/php.ini is not a general file

[-r/etc/php.ini]/etc/php.ini whether the current user has readable permissions

[-w/etc/php.ini] Determine if/etc/php.ini Current user has writable permissions

[-x/etc/php.ini] Determines whether the current user has executable permissions/etc/php.ini

can use the command: Echo $? To see the results after each command execution, successfully returning 0, and returning a number other than 0

Writing shell Scripts--judging the user's parameters