Linux
Notes for Professionals
®
Notes for Professionals
50+ pages
of professional hints and tricks
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,Contents
About ................................................................................................................................................................................... 1
Chapter 1: Getting started with GNU/Linux ..................................................................................................... 2
Section 1.1: Useful shortcuts .......................................................................................................................................... 2
Section 1.2: File Management Commands .................................................................................................................. 3
Section 1.3: Hello World ................................................................................................................................................. 5
Section 1.4: Basic Linux Utilities .................................................................................................................................... 5
Section 1.5: Searching for files by patterns in name/contents ................................................................................. 6
Section 1.6: File Manipulation ........................................................................................................................................ 7
Section 1.7: File/Directory details ................................................................................................................................. 8
Chapter 2: Detecting Linux distribution name and version .................................................................. 11
Section 2.1: Detect what debian-based distribution you are working in ............................................................... 11
Section 2.2: Detect what systemd-based distribution you are using .................................................................... 11
Section 2.3: Detect what RHEL / CentOS / Fedora distribution you are working in ............................................ 12
Section 2.4: Uname - Print information about the current system ........................................................................ 13
Section 2.5: Detect basic information about your distro ........................................................................................ 13
Section 2.6: Using GNU coreutils ................................................................................................................................ 13
Section 2.7: Find your linux os (both debian & rpm) name and release number ................................................ 14
Chapter 3: Getting information on a running Linux kernel ................................................................... 15
Section 3.1: Getting details of Linux kernel ................................................................................................................ 15
Chapter 4: Shell ........................................................................................................................................................... 16
Section 4.1: Changing default shell ............................................................................................................................ 16
Section 4.2: Basic Shell Utilities .................................................................................................................................. 17
Section 4.3: Create Your Own Command Alias ........................................................................................................ 18
Section 4.4: Locate a file on your system ................................................................................................................. 18
Chapter 5: Check Disk Space ................................................................................................................................ 19
Section 5.1: Investigate Directories For Disk Usage ................................................................................................. 19
Section 5.2: Checking Disk Space .............................................................................................................................. 21
Chapter 6: Getting System Information ......................................................................................................... 23
Section 6.1: Statistics about CPU, Memory, Network and Disk (I/O operations) .................................................. 23
Section 6.2: Using tools like lscpu and lshw .............................................................................................................. 23
Section 6.3: List Hardware .......................................................................................................................................... 24
Section 6.4: Find CPU model/speed information ..................................................................................................... 25
Section 6.5: Process monitoring and information gathering .................................................................................. 26
Chapter 7: ls command ........................................................................................................................................... 28
Section 7.1: Options for ls command ......................................................................................................................... 28
Section 7.2: ls command with most used options .................................................................................................... 28
Chapter 8: File Compression with 'tar' command ...................................................................................... 30
Section 8.1: Compress a folder ................................................................................................................................... 30
Section 8.2: Extract a folder from an archive .......................................................................................................... 30
Section 8.3: List contents of an archive .................................................................................................................... 30
Section 8.4: List archive content ................................................................................................................................ 31
Section 8.5: Compress and exclude one or multiple folder .................................................................................... 31
Section 8.6: Strip leading components ...................................................................................................................... 31
Chapter 9: Services .................................................................................................................................................... 32
Section 9.1: List running service on Ubuntu .............................................................................................................. 32
Section 9.2: Systemd service management ............................................................................................................. 32
,Chapter 10: Managing Services ........................................................................................................................... 33
Section 10.1: Diagnosing a problem with a service .................................................................................................. 33
Section 10.2: Starting and Stopping Services ........................................................................................................... 33
Section 10.3: Getting the status of a service ............................................................................................................. 34
Chapter 11: Modifying Users .................................................................................................................................. 35
Section 11.1: Setting your own password ................................................................................................................... 35
Section 11.2: Setting another user's password .......................................................................................................... 35
Section 11.3: Adding a user .......................................................................................................................................... 35
Section 11.4: Removing a user .................................................................................................................................... 35
Section 11.5: Removing a user and its home folder ................................................................................................. 35
Section 11.6: Listing groups the current user is in ..................................................................................................... 35
Section 11.7: Listing groups a user is in ...................................................................................................................... 35
Chapter 12: LAMP Stack ........................................................................................................................................... 36
Section 12.1: Installing LAMP on Arch Linux ............................................................................................................... 36
Section 12.2: Installing LAMP on Ubuntu ................................................................................................................... 37
Section 12.3: Installing LAMP stack on CentoOS ....................................................................................................... 38
Chapter 13: tee command ...................................................................................................................................... 40
Section 13.1: Write output to stdout, and also to a file ............................................................................................. 40
Section 13.2: Write output from the middle of a pipe chain to a file and pass it back to the pipe ..................... 40
Section 13.3: write the output to multiple files .......................................................................................................... 40
Section 13.4: Instruct tee command to append to the file ....................................................................................... 40
Chapter 14: Secure Shell (SSH) ............................................................................................................................ 42
Section 14.1: Connecting to a remote server ............................................................................................................. 42
Section 14.2: Installing OpenSSH suite ....................................................................................................................... 42
Section 14.3: Configuring an SSH server to accept connections ............................................................................ 43
Section 14.4: Passwordless connection (using a key pair) ...................................................................................... 43
Section 14.5: Generate public and private key ......................................................................................................... 43
Section 14.6: Disable ssh service ................................................................................................................................ 43
Chapter 15: SCP ............................................................................................................................................................ 45
Section 15.1: Secure Copy ............................................................................................................................................ 45
Section 15.2: Basic Usage ........................................................................................................................................... 45
Chapter 16: GnuPG (GPG) ........................................................................................................................................ 46
Section 16.1: Exporting your public key ...................................................................................................................... 46
Section 16.2: Create and use a GnuPG key quickly .................................................................................................. 46
Chapter 17: Network Configuration .................................................................................................................. 47
Section 17.1: Local DNS resolution .............................................................................................................................. 47
Section 17.2: Configure DNS servers for domain name resolution ........................................................................ 47
Section 17.3: See and manipulate routes .................................................................................................................. 47
Section 17.4: Configure a hostname for some other system on your network .................................................... 48
Section 17.5: Interface details ..................................................................................................................................... 49
Section 17.6: Adding IP to an interface ...................................................................................................................... 50
Chapter 18: Midnight Commander ..................................................................................................................... 52
Section 18.1: Midnight Commander function keys in browsing mode .................................................................... 52
Section 18.2: Midnight Commander function keys in file editing mode ................................................................. 52
Chapter 19: Change root (chroot) ...................................................................................................................... 54
Section 19.1: Requirements ......................................................................................................................................... 54
Section 19.2: Manually changing root in a directory ............................................................................................... 54
Section 19.3: Reasons to use chroot .......................................................................................................................... 55
Chapter 20: Package Managers .......................................................................................................................... 56
, Section 20.1: How to update packages with the apt package manager .............................................................. 56
Section 20.2: How to install a package with the pacman package manager ...................................................... 56
Section 20.3: How to update packages with the pacman package manager ..................................................... 56
Section 20.4: How to update packages with yum ................................................................................................... 57
Chapter 21: Compiling the Linux kernel ........................................................................................................... 58
Section 21.1: Compilation of Linux Kernel on Ubuntu ............................................................................................... 58
Credits .............................................................................................................................................................................. 59
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