Document and Directory Management focus

• Absolute path: "Must be from the root directory/write"; Relative path: "Not/write"
• Special directories are:.,..,-, ~, ~account need attention;
• Directory-related commands are: CD, mkdir, RmDir, PWD and other important commands;
• RmDir can only delete empty directories, to delete non-empty directories need to use the "rm-r" command;
• The commands that the user can use are searched according to the directory specified in the PATH variable;
• Different identities (root and normal) system default PATH is not the same. The difference is greater in/sbin,/usr/sbin;
• LS can view the properties of the file, especially the-D,-A,-l and other options are particularly important!
• File copy, delete, move can be used separately: CP, RM, MV and other commands to operate;
• Check the contents of the file (read the document) available commands include: Cat, TAC, NL, more, less, head, tail, OD, etc.
• Cat-n and NL can display the line number, but by default, the blank line will not be the same number;
• The purpose of touch is to modify the file's time parameters, but can also be used to create an empty file;
• There are three time parameters for a file record, which is access times (atime), status (CTime), modification (mtime), and LS is mtime by default.
• In addition to the traditional rwx permissions, in the Ext2/ext3 file system, you can also use chattr and lsattr to configure and observe hidden properties. Common +a that include only new data and +i properties that are completely unable to change the file.
• When new files/directories are created, the default permissions for new files are regulated using Umask. The default directory full permission is drwxrwxrwx and the file is-rw-rw-rw-.
• When a file has special permissions for suid, the user temporarily has permission to the program owner when the user runs the binary program.
• When a directory has special permissions for Sgid, the group of files created on behalf of the user under this directory will be the same as the group name for that directory.
• When a directory has special permissions for Sbit, the files created by the user in that directory are deleted only by itself and by Root!
• The type of the observed file can be observed using the files command;
• The full file name of the search command can be either which or type, both of which are searched through the PATH variable for the file name;
• The full filename of the search file can be searched using Whereis or locate to the database file without actually searching the file system;
• Find can add many options to directly query the filesystem to get the file name you want to know.

Document and Directory Management focus