perl中 -e, -z, -s, -M, -A, -C, -r, -w, -x, -o, -f, -d , -l 含义

Description taken from the official documentation of Perl:

• -r File is readable by effective uid/gid.
• -w File is writable by effective uid/gid.
• -x File is executable by effective uid/gid.
• -o File is owned by effective uid.

• -R File is readable by real uid/gid.
• -W File is writable by real uid/gid.
• -X File is executable by real uid/gid.
• -O File is owned by real uid.

• -e File exists. #文件是否存在
• -z File has zero size (is empty).
• -s File has nonzero size (returns size in bytes).#判断文件是否为空文件

#举个列子，-s使用，

#ef.pl

#! /usr/bin/perl

if ( -s "./file.test" ){#file.test为空文件

print "No zero size continue!\n";

}else{print "Zero size poweroff!\n";

}

perl ef.pl

Zero size poweroff!

• -f File is a plain file.
• -d File is a