Gaurav Masand su starts a shell as another user. It is commonly used to switch to the root account or to test commands under a different account. Switch to another user su – username The hyphen starts a login shell, so the target user’s environment is loaded. Switch to root su – This normally asks for the … Read more
If a user needs to run a small set of administrative commands, the preferred approach is usually a carefully scoped sudo rule rather than making arbitrary programs setuid root. Use sudo with least privilege Edit sudo policy with visudo or a file under /etc/sudoers.d/. Grant only the exact commands required, and avoid broad rules such … Read more
bzip2 is a command-line tool for compressing files on Linux. It usually creates files with a .bz2 extension. Compress a file This creates filename.txt.bz2 and removes the original file by default. Decompress a file To keep the original file while compressing or decompressing, use -k.
adjtimex exposes low-level Linux kernel timekeeping parameters. It is mainly useful for diagnostics, experimentation, and older time-synchronisation workflows; most systems should use a supported time service such as chrony or systemd-timesyncd for normal clock synchronisation. Inspect current parameters adjtimex -p This displays kernel time variables such as tick and frequency adjustments. Use caution when changing … Read more
Legacy hard drive performance note with safer modern guidance.
Modern notes on customising the GRUB 2 boot menu, themes, /etc/default/grub, and safely regenerating bootloader configuration.
dos2unix converts text files from Windows line endings to Unix/Linux line endings. This is useful when shell scripts edited on Windows fail with strange errors. Convert a file After converting, make sure the script has execute permission if you want to run it directly. Check file type If the file shows CRLF line terminators, dos2unix … Read more
Modern Linux commands for inspecting PCI, USB, storage, CPU, firmware, and driver information.
The message target is busy means some process still has a file, directory, or working directory open on the filesystem you are trying to unmount. Common causes A terminal is currently inside the mount point. A file manager has the directory open. An editor or media player still has a file open. A background process … Read more
Linux has two common ways to search for files: find, which searches the filesystem directly, and locate, which searches a prebuilt filename database. Use find for current results find /path -name ‘filename’ find /path -iname ‘*.log’ find reflects the current filesystem state and supports filters for type, size, owner, modification time, permissions, and more. Use … Read more