The shell is a command-line interface (CLI) program that provides an interactive way for users to interact with the Unix-like operating system. It interprets user commands and executes them on behalf of the user. The basic responsibilities of a shell include:

Command interpretation : The shell interprets the commands entered by the user and translates them into actions that the operating system can understand and execute.

Command execution : The shell executes the commands entered by the user, launching processes and programs as necessary. It manages the execution of commands, including handling input/output redirection, piping, and job control.

Environment management : The shell manages the environment in which commands are executed, including environment variables, working directory, and file descriptors. It allows users to set, modify, and export environment variables, customize the shell environment, and control the behavior of commands.

File and directory management : The shell provides commands for navigating the file system, listing files and directories, creating, copying, moving, and deleting files, and managing file permissions and ownership. It allows users to manipulate files and directories from the command line.
I/O redirection : The shell allows users to redirect input and output streams of commands, enabling them to read input from files or other commands, and write output to files or other destinations. It supports input/output redirection operators such as '<', '>', and '|'.

Pipeline processing : The shell supports the creation of pipelines, allowing users to chain multiple commands together, with the output of one command serving as the input to the next command. It manages the flow of data between commands in a pipeline and ensures proper synchronization and communication.

Job control : The shell provides facilities for managing running processes and jobs, including starting, stopping, suspending, resuming, and terminating processes. It allows users to run commands in the background, foreground, or suspended state, and monitor their execution status.

Scripting : The shell supports scripting, allowing users to write shell scripts (text files containing sequences of shell commands) to automate repetitive tasks, customize the shell environment, and create complex command sequences.