everything about linux distro and not only
The pipe sends the output of one command to the input of the next, and the output is consumed. The command | grep ‘pattern’ sends the output to the grep, and the grep prints the matching lines. But the original output is gone: the command‘s output was piped and not saved. The tee solves the…
28 – fdisk command fdisk is a command-line tool for managing partition tables on HDDs, SSDs, and other storage devices. You can create, delete, resize partitions, change their types, or check their status. Key point: fdisk edits the partition table, not the filesystem. Always back up data before modifying partitions. a – fdisk fdisk is…
Installing software is only half of package management. The other half is taking it away and keeping it current. Removing a package is not the reverse of installing it — configuration files are preserved by default, dependencies that were installed automatically are left behind, and packages that other packages depend on cannot be removed without…
MACVLAN and IPVLAN are two virtual network drivers that solve a problem veth pairs and bridges cannot: they allow a single physical interface to present multiple distinct network identities without creating a bridge. A MACVLAN interface gets its own MAC address, so the external switch sees it as a separate physical host. An IPVLAN interface…
A command reads from the standard input, and the input usually comes from the file or the pipe. But sometimes the input is the short, the inline, and the not worth the file. The cat << EOF feeds the block of the text to the cat without the temporary file. The grep ‘pattern’ <<< “$variable”…
These three commands form the backbone of filesystem management on Linux. fsck checks and repairs filesystems, mkfs creates them, and dd copies raw data between devices and files. Together they let you build, verify, and clone storage at a low level. Key point: These tools operate on filesystems and raw devices — not on individual…
Every program running on a Linux system is a process. The shell you type into is a process. The web server serving a page is a process. The kernel’s background workers, the login session, the editor, the compiler — all processes. When something is slow, or a service is not responding, or a program is…
An overlay network is a virtual network built on top of an existing physical network. The physical network, called the underlay, provides basic IP connectivity between hosts. The overlay creates a separate logical topology on top of it, encapsulating one type of packet inside another so that the underlay only sees the outer headers. The…
The pipe connects the standard output of one command to the standard input of the next. But the pipe has a limitation: the two commands must be adjacent in the pipeline. The diff <(ls dir1) <(ls dir2) compares the output of the two ls commands, but the diff expects the file arguments, not the standard…
ping and traceroute are two of the most fundamental network diagnostic tools. ping tells you whether a host is reachable and how fast the round trip is. traceroute tells you which path packets take to get there, hop by hop. Key point: Both tools use ICMP (Internet Control Message Protocol) by default. Some networks block…