Guide to Getting Bash

1. Checking Your Current Shell

To find out which shell you are using, run:

echo $SHELL

This command will display one of the following:

• sh (Bourne shell)
• csh (C shell)
• ksh (Korn shell)
• bash (Bash shell) If you see any other result (like tcsh), you may not be using bash.

2. Switching to Bash

To check if bash is available on your system, type:

bash

If a new prompt like bash3 $ appears, bash is installed. To return to your current shell, type:

exit

Note

If you get a “not found” message, bash might not be installed. Contact your system administrator to see if it's installed in an inaccessible directory, or proceed with installing it if necessary.

3. Making Bash Your Default Shell

You can temporarily start bash from any other shell by typing bash, but it’s better to make it your default login shell.

Steps to install bash as your login shell:

1. Find bash on your system Use one of the following commands to locate where bash is installed:

   whereis bash
   whence bash
   which bash

   If these don't work, try the following complex command:

   grep bash /etc/passwd | awk -F: '{print $7}' | sort -u

2. Set bash as your login shell Once you’ve identified where bash is installed (e.g., /bin/bash or /usr/local/bin/bash), run:

   chsh /usr/local/bin/bash

   (Replace /usr/local/bin/bash with the correct path found in the previous step.)

3. Confirm the Change You may be prompted for your password. After entering it, log out and back in to start using bash as your default shell.

Note

If these steps don’t work, you may need assistance from your system administrator.

Files in UNIX 📄

Although not all command arguments are files, files are fundamental in any UNIX system. Files can hold various types of information, and three main types are crucial:

1. Regular Files

   • Also known as text files.
   • These contain readable characters and are the most common type of file.
   • Example: This guide was created using several regular files, which hold text and human-readable formatting instructions for processing.

2. Executable Files

   • Also referred to as programs.
   • These are files that can be executed as commands. Some are not readable by humans, while others, like shell scripts, are special text files that can be run by the system.
   • The shell itself (e.g., bash) is a non-human-readable executable file.

3. Directories

   • Directories are like folders that can contain other files and subdirectories.
   • They organize files into a hierarchical structure, helping to manage and access files efficiently.

These file types form the backbone of working in a UNIX system, allowing users to store, execute, and organize data effectively.