The uname command identifies elementary information about the system including its hostname. uname → shows only the kernel name. uname -a → showing all information Kernel name(1), hostname(2), kernel release(3), date and time of the kernel built(4), machine and hardware name(5), processor type(6), hardware platform(7), operating system name(8). More separate commands to try on uname
We can see all cpu info using the command lscpu
man pages: Press h to get help on navigation, press q to quit and return to the command prompt, use the Up and Down arrow keys to scroll up and down, and the PgUp and PgDn keys to scroll one page at a time. KEYS WHICH CAN HELP IN NAVIGATION: apropos command: It is alias of the command man -k {half_remembered_cmd_name} → This command allows us to perform keyword search on manual pages incase we have forgot what the command name is. Note Before we run the keyword search we need to run the command mandb ...
Navigate Linux Directory Tree - Practice questions: Note Do it yourself, try to use the existing knowledeg you had learned from the chapter 1. If you get stuck , you can look into AI tools but don’t overuse them. ...
Main commands: Commands Short description ls -l Lists files in a long format showing permissions, owner, and size. ls -a Lists all files, including hidden ones (those starting with a dot). ls -ld Lists details of the directory itself rather than its contents. ls -lh Lists files in long format with file sizes in human-readable format (KB, MB). ls -lt Lists files sorted by modification time, newest first. ls -ltr Lists files sorted by modification time in reverse order (oldest first). ls -R Lists all files in the current directory and all subdirectories recursively. pwd Prints the full path of the current working directory. cd .. Moves one level up into the parent directory cd dir_name Changes the current directory to the specified folder cd ~ Moves directly to the current user’s home directory. cd - Switches back to the previous directory you were in. cd Shortcut to return to the home directory. tree -a Displays all files and directories in a tree structure, including hidden ones. tree -d Displays only directories in the tree structure. tree -h Displays the tree structure along with human-readable file sizes. tree -f Displays the full path prefix for each file in the tree. tree -p Displays the tree structure along with file permissions. tty Prints the file name of the terminal connected to standard input. uptime Shows how long the system has been running and the current load. clear Clears the terminal screen for a fresh workspace. which command_name Shows the full path of the executable for a command. whereis command_name Locates the binary, source, and manual page files for a command. type command_name Explains how a command name would be interpreted (alias, builtin, or file). uname Prints the name of the operating system kernel. uname -a Prints all available system information in one line. uname -s Displays the kernel name. uname -n Displays the network node hostname. uname -r Displays the kernel release version. uname -v Displays the kernel version date and build info. uname -m Displays the machine hardware architecture (e.g., x86_64). uname -p Displays the processor type or “unknown”. uname -i Displays the hardware platform or “unknown”. uname -o Displays the operating system name (e.g., GNU/Linux). lscpu Displays detailed information about the CPU architecture. man cmd_name Opens the official manual page for a specific command. man -k cmd_name Searches the manual descriptions for a specific keyword. appropos cmd_name Searches the manual pages for a keyword (same as man -k). cmd_name --help Displays a brief summary of a command’s options and usage. cmd_name -? An alternative flag used by some programs to show help. ls -l /usr/share/doc/cmd_name Checks for additional offline documentation files for a program.
RHEL supports seven types of files: Regular Directory Block special device → Used by the OS to communicate with peripheral devices. character special device → Used by the OS to communicate with peripheral devices. symbolic link named pipe → Used in IPC(Inter Process Communication) socket → Used in IPC(Inter Process Communication) Regular Files: Regular files may contain text or binary data. These files may be shell scripts or commands in the binary form. When you list a directory, all line entries for files in the output that begin with the hyphen character (-) represent regular files. Example: The - before the rw permission depicts that it is a regular file. file command: Returns the specific type of data that the file contains, in this case it’s ASCII text. stat command: It simply states that the file is a regular file. Directory Files: Directories are logical containers that hold files and subdirectories. The letter “d” at the beginning of each line entry identifies the file as a directory. file command on /usr directory: stat command on /usr directory: Block and character special device files: What are Device files? Each piece of hardware in the system has an associated file in the /dev directory that is used by the system to communicate with that device. This type of file is called a device file. Types of device files: Block → On the initial with the letter b we can distinguish it’s Block device file. Character/ raw → On the initial with the letter c we can distinguish it’s character device file. file command on both of the directories → /dev/console and /dev/nvme0n* stat command on both of the directories → /dev/console and /dev/nvme0n* Important concepts related to device files(PAY ATTENTION): Concept of major number: Let’s elaborate the picture ...
Archive, compress, unpack, and uncompress files using tar, star, gzip, and bzip2 Create and edit text files Create, delete, copy, and move files and directories Create hard and soft links