The usermod command is a user management tool to modify user account information like username, user ID, default shell, home directory, and many more.

The which command locates the executable command or file location in the user’s environmental path. It will give you the complete path an executable command or file is pointing towards in your file system.

The whatis command is used to fetch a one-line description of the specified command or tool from the manual pages in your Linux system.

The whereis command is used to find the paths of binary, source, and manual files for a specified command, similarly to the find command but consuming less memory.

The locate command is used to quickly search for files or directories within the indexes in the database file known as updatedb.

The find command is an advanced tool for searching files or directories rigorously in your file system, taking a little longer time than its alternative tools like the locate command.

On Linux, you have multiple tools like which, whereis, locate, and find that can help you find the absolute path for files and directories in your system.

The environment variables are a set of key-value pairs that define the current environment and can affect the behavior of the ongoing programs that are executed in the environment.

The bash uses multiple profiles, also known as shell configuration files, to configure the user’s interactive login or non-login shell.

Whenever you operate a Linux system behind the scenes, you might be encountering the interactive login or non-login shell that you are not aware of.

The printenv command is an alternative to the env command used to fetch the value of a specified variable name (key) used as an argument.

The env command is an advanced version of printenv with a few more features to tweak your environment variables, like setting new environment variables, printing all environment variables, or executing a command in a modified environment.

The source is a built-in command-line tool that reads and executes the commands from the specified file as its argument in the current shell.

The bash (Bourne-Again SHell) is a sh-compatible command-line interpreter that reads from standard input or from a file and gives you the resulting output.

Bash, an acronym for “Bourne-Again SHell“, is a superset of the shell (or sh) program written by Brian Fox for the GNU Project as a replacement for the traditional Bourne Shell (or sh).

To avoid jumping into the directory to execute your local program or script, you can add their paths to the $PATH variable to access them from anywhere.

In Linux, multiple long commands can be easily replaced with a single short command using the alias command.

In Linux, the alias command is used to create shortcuts for long commands that have the same functionality as if you were writing the whole command.

The eval command is used to execute specified arguments as a single command in the current command-line processing and return its result.

The WC command is used to count various parameters from the specified file, like the number of lines, word counts, byte counts, character counts, and many more.

In this article, you will learn to count the number of string occurrences in a text file using the grep, wc, and tr commands, including the VIM text editor.