What is the Use of Util-Linux?

Util Linux is a collection of essential utility programs for Linux operating systems. It is a package that provides various tools to perform essential system administration tasks and general utilities to manage and maintain a Linux-based system.

These utilities are typically low-level and essential for the proper functioning of the system. util Linux is usually distributed as open-source software and is an integral part of most Linux distributions.

• System Administration:
  Util Linux includes tools that are vital for system administration tasks, such as managing disks and partitions, formatting file systems, and handling swap space.
• File System Utilities:
  It offers various utilities to work with different file systems, including mounting and unmounting file systems, checking and repairing file systems, and resizing partitions.
• Terminal Utilities:
  Util Linux contains several terminal-related utilities, including terminal emulators and tools for working with the terminal.
• Process Management:
  It provides tools for managing processes, such as viewing running processes, sending signals to processes, and terminating processes.
• User and Group Management:
  Util Linux includes utilities for managing users and groups on the system, such as adding, modifying, and deleting user accounts and groups.
• Network Utilities:
  It offers various networking tools, including tools for working with network interfaces, querying network information, and managing network connections.
• Miscellaneous Utilities:
  Util Linux also includes several miscellaneous utilities, such as tools for working with date and time, random number generation, and hardware-related information.

FHS (Filesystem Hierarchy Standard) Compliance Notes

Util Linux, being a collection of essential utility programs for Linux, aims to adhere to the Filesystem Hierarchy Standard (FHS) to ensure consistency in the organization of files and directories across different Linux distributions. Here are some compliance notes related to util Linux in terms of FHS:

Installation Directories:
The executables and utilities provided by util Linux are typically installed in the standard binary directories, such as /bin, /sbin, and /usr/bin. These directories are where essential executable binaries for regular users and system administrators are placed, and util Linux utilities fit in accordingly.

Shared Libraries:
If util Linux includes shared libraries, they are generally installed in the appropriate library directories like /lib and /usr/lib. This allows other programs and utilities on the system to dynamically link to these shared libraries when needed.

Configuration Files:
Configuration files specific to util Linux tools, if any, are placed in the /etc directory as per FHS guidelines. These files contain settings and parameters for various utilities, allowing system administrators to configure them according to their needs.

Temporary Files:
Util Linux utilities are expected to follow the FHS recommendation regarding temporary files. If any temporary files are generated during the operation of util Linux tools, they should be placed in the /tmp directory, which is the standard location for temporary files.

Documentation:
Documentation related to util Linux utilities is usually placed in the /usr/share/doc/util Linux directory, following the FHS convention for documentation files.

User Home Directories:
Util Linux tools that deal with user and group management to interact with the user home directories, which are typically found under the /home directory as prescribed by FHS.

Device Nodes:
If any of the util Linux utilities interact with devices directly, they should access the corresponding device nodes in the /dev directory, which follows FHS guidelines for representing physical and virtual devices.

Contents of Util Linux

The specific utilities included in util Linux can vary based on the version and distribution. However, some of the common utilities found in util Linux are mentioned below.

• fdisk:
  A partitioning tool used to create, modify, and delete disk partitions on storage devices.
• mount:
  Used to mount various file systems on directories in the Linux file hierarchy.
• umount:
  Used to unmount previously mounted file systems.
• swapon:
  Used to enable swapping space on devices or files.
• swapoff:
  Used to disable swapping space on devices or files.
• kill:
  Sends signals to processes, allowing users to manage processes, terminate them, etc.
• more and less:
  Both are terminal pager utilities used to view the contents of files one screen at a time.
• cal:
  Displays a calendar in the terminal.
• hwclock:
  Used to access or set the hardware clock of the system.
• dmesg:
  Prints or controls the kernel ring buffer, showing kernel-related messages.
• findmnt:
  Displays information about mounted file systems.
• losetup:
  Sets up and controls loop devices, which allow file access as block devices.
• blkid:
  Prints information about block devices, such as UUID and file system type.
• uuidgen:
  Generates universally unique identifiers (UUIDs).
• logger:
  Used to send messages to the system log.

Installation of Util Linux

The installation of util Linux can vary depending on the Linux distribution you are using. In most cases, util Linux is included by default in the base installation of the operating system. However, if for some reason it's not installed, or you need a specific version, you can use the package manager of your Linux distribution to install it.

Here are the installation commands for some popular Linux distributions:

Debian/Ubuntu:

Util Linux is likely pre-installed on Debian and Ubuntu systems. However, if you need to install or update it, you can use the apt package manager:

Red Hat/Fedora/CentOS:

On Red Hat-based distributions, you can use dnf or yum (for older versions) to install util Linux:

or

Arch Linux:

Arch Linux usually has util Linux installed by default. If not, you can install it using pacman:

openSUSE:

On openSUSE systems, you can use zypper to install util Linux:

After installing util Linux, you will have access to a wide range of utility programs that are essential for system administration, disk management, file system operations, and other low-level tasks on your Linux-based operating system.

Short Descriptions

Here are one-line descriptions for the given commands:

• agetty:
  An alternative Linux getty that configures and manages terminal lines.
• arch:
  Display machine architecture information.
• blockdev:
  Call block device ioctls from the command line.
• cfdisk:
  An interactive partition editor for creating disk partitions.
• chkdupexe:
  Check for duplicate executables in PATH and the current directory.
• col:
  Filter reverse line feeds (carriage returns) from the input.
• colcrt:
  Filter out control characters, leaving only form feeds and ASCII text.
• colrm:
  Remove columns from a file.
• column:
  Format data into multiple columns.
• ctrlaltdel:
  A tool to manage Ctrl-Alt-Del key combination.
• cytune:
  Control cyclomatic and essential complexity of C code.
• ddate:
  Convert Gregorian dates to Discordian dates.
• elvtune:
  Tune elevator parameters for IDE-style elevators.
• fdformat:
  Low-level format a floppy disk.
• fsck.cramfs:
  Check and repair CramFS file systems.
• fsck.minix:
  Check and repair Minix file systems.
• getopt:
  Parse command-line options.
• hexdump:
  Display file contents in hexadecimal, ASCII, decimal, or octal.
• ipcrm:
  Remove System V interprocess communication (IPC) objects.
• ipcs:
  Report System V interprocess communication (IPC) status.
• isosize:
  Output the size of an ISO 9660 file system.
• line:
  Read one line from stdin.
• logger:
  Send messages to the system log.
• look:
  Display lines beginning with a specific string.
• losetup:
  Set up and control loop devices.
• mcookie:
  Generate random cookies (magic cookies).
• mkfs:
  Create a file system on a device or file.
• mkfs.bfs:
  Create Boot File System (BFS) file system.
• mkfs.cramfs:
  Create CramFS compressed file system.
• mkfs.minix:
  Create Minix file system.
• mkswap:
  Set up a Linux swap area.
• namei:
  Follow a pathname until a terminal point is found.
• parse.bash:
  Parse positional arguments for bash scripts.
• parse.tcsh:
  Parse positional arguments for tcsh scripts.
• pg:
  Display text one screen at a time (page).
• pivot_root:
  Move the root file system to a new location and execute new init.
• ramsize:
  Show or set the RAM disk size.
• raw:
  Set the raw mode of a terminal.
• rdev:
  Get or set the root device (initial RAM disk).
• readprofile:
  Read kernel profiling data.
• rename:
  Rename multiple files at once.
• renice:
  Alter the priority of running processes.
• rev:
  Reverse lines of a file or input stream.
• rootflags:
  Show or set root flags for the kernel.
• script:
  Make a typescript of terminal session.
• setfdprm:
  Set or get the parameters of a floppy disk.
• setsid:
  Run a program in a new session.
• setterm:
  Set terminal attributes.
• sfdisk:
  Partition table manipulator for Linux.
• test.bash:
  Evaluate conditional expressions for bash scripts.
• test.tcsh:
  Evaluate conditional expressions for tcsh scripts.
• tunelp:
  Set various parameters for disk and tape devices.
• ul:
  Filter underlined text to the correct representation.
• vidmode:
  Show or set the video mode used during boot.
• whereis:
  Locate the binary, source, and manual page files for a command.
• write:
  Send messages to another user.