Linux note--facl,case statement and disk File system

• Facl:filesystem access Control list to save additional access controls with file extensions

• Access order for general permissions: Owner--group--other

• If there is an access order for additional permissions: Owner--facl.user--group--facl.group--other

• Set additional permissions: Setfacl View additional permissions: Getfacl

• -m set-X cancel-M U:uid: Privilege set additional user rights-M G:gid: Privilege Set Additional group permissions-X u:uid cancel-M Dg:gid extended permissions on directory and its subdirectories

• Terminal type: Consols: Console pty: Physical terminal TTY: Virtual terminal-ttys: Serial terminal pts/#: Pseudo terminal

• W shows who logged in and shows what the user is doing who displays the user's logon time WhoAmI show this user

• Last Displays the login log history of the current system/var/wtmp/file record information-N # displays only the most recent logon information LASTB display user error logon attempts/var/log/btmp file record information Lastlog display the last successful login for each user on the system Record Information-u username Displays the specified user

• BaseName directly obtains the file base name, cannot take the directory name of the command itself, the script itself executes script when the script path base name

• Mail:echo "Mail Content" | Mail-s "Mail name" (root or send mail to other users)

• Generate random Number:

• RANDOM: Variable within range 0-32768 ($RANDOM)

• Case

• Case $ variable in

• value1)

• statement;;

• value2)

• statement;;

• ESAC (end)

• Disk Management:

• Mechanical HDD: Factory (low-level format, partition disk sector)--partition (partitioning)--File system

• Mbr:master boot Record master boot records, stored in 0 tracks 0 sectors, total 512 bytes, independent of the operating system

• 512: Divided into 3 segments, 446byte--boot loader bootloader program code 64byte--each 16 bytes to identify a partition, so the hard disk can only be divided into 4 primary partitions 2--mark the MBR is valid

• Partition: There can be only four primary partitions, but the extended partition may have multiple logical partitions, and only one (primary + extended <=4) partition in the extended partition is per cylinder, and storage is

• File system, the management software is not on the partition (somewhere on the disk), but the data is on the partition

• File type: the

• Hard links: Files of different paths point to the same inode node (-n source file link file name)

• 1. Cannot apply to directory

• 2. Cannot cross file system

• 3. Creating a hard link increases the number of file links

• Symbolic Link: path to another file (-n-s source file Link file name-V display procedure)

• 1. Available Applications and catalogs

• 2. Can cross file system

• 3. No increase in the number of links

• 4. Size is the number of characters that are included in the fixed path

• Du: Displays all file sizes of the directory-s displays the size of the directory-N Conversion display units

• DF: Display disk Information-H conversion display Unit-I display inode information

• Device files:

• B: per block, random access (hard disk)

• C: By character, linear access (keyboard)

• Device number:

• Main device number: Identifies the device type

• Secondary device number: Identifies a different device of the same type

• To create a character block device file:

• Mknod [option] name type (B/C) primary number (-m:mod permission)

• Device file name of the device for the hard disk:

• IDE (ATA): Hda SATA:SDA USB:SDC Scsi:sdb (a b c d.. Distinguish between different devices of the same type)

• SDA:SDA1 sda2 Sda3 sda4 is the primary partition number (the system will reserve 1-4) the extended partition can only be 5, and cannot be used directly, and a logical partition should be established on it.

• Linux Supported file systems:

• ext2 ext3 ext4 XFS reiserfs NFS OCFS2 GFS2 JFS FAT32 NTFS iso9660 CIFS .....

• To manage disk partitions:

• Fdisk-l View all disks can also be specified with the device path view Fdisk/dev/sda2

• FDISK/DEV/SDA: Disk Creation Delete interaction mode (disk device cannot be partitioned behind must)

• P: Display the current hardware partition including unsaved changes N: Create new Partition (e: Extended partition P: Primary partition) d: Delete a partition w: Save exit Q: Do not save exit T: Modify partition type (L: Show supported partition types) L show supported partition types

• Cat/proc/partitions: View kernel-recognized partitions

• Partprobe: Reread partition table (Partx can also)

• 
  

This article is from the "stupid Bird first-FAI" blog, please be sure to keep this source http://benniaoxianhui.blog.51cto.com/10463960/1679204

Linux note--facl,case statement and disk File system