I read the book “Linux Command Line (Cover All Essential Linux Commands)“.
There are a lot of useful Tips in Linux. I would like to show some of them from the book!
👽 Filesystem
I have never seen the following meanings of Linux drectories.
It is so good for me!
- /bin : Basic command line utilities for all users
- /boot : Commands to boot on computer
- /dev : All devices files
- /etc : A set of system configuration
- /home : Users’ data files
- /lib : Program libraries
- /mnt : Mount point of removable various devices
- /opt : Optional files and packages loaded onto the system
- /sbin : System administration commands
- /tmp : Temporary files
- /usr : Programs and data available to all users
- /proc : All kernel-related processes
- /root : Superusers’ home directory
- /var : Variable data like system logs, prit spool files and etc.
🐠 Linux Symbols
<
: Get input from afile to a command>
: Send output from a command to file>>
: Append output a file
$ cat file1.txt >> file2.txt |
|
: Send cmd1 output to cmd2 input
$ ls -al /etc | less |
;
: Combile two or more commands\
: Escape the special character./
: Run a script in the current directory..
: Parent directory~
: Home direcotory$
: Variable prefix for valiable name and value$$
: Show the running processes number!!
: Repeat the last command!string
: Run recent cmd that begins with string
$ !cat |
🐰 Access Permissions
rwx
signify the access permissions which can be described by a number from 1 to 7.
- 4(r) : Read Permissions
- 2(w) : Write Permissions
- 1(x) : Execute Permissions
Access permissions for a file are devided in to three:
- User Permissions
- Group Permissions
- Others Permissions
🎂 About Run Levels
- Level 0 : Halt-the system is in the process of shutting down
- Level 1 : Single-user mode. Only small set of kernel process running
- Level 2 : Basic Multi-user mode without network services started
- Level 3 : Full Multi-user mode with network services started
- Level 4 : User defined mode
- Level 5 : Full multiuser mode with X window
- Level 6 : System reboot
🖥 Recommended VPS Service
VULTR provides high performance cloud compute environment for you.
Vultr has 15 data-centers strategically placed around the globe, you can use a VPS with 512 MB memory for just $ 2.5 / month ($ 0.004 / hour).
In addition, Vultr is up to 4 times faster than the competition, so please check it => Check Benchmark Results!!