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I often work with various shells to interact with my operating system and run commands. Two of the most commonly used shells are the Bourne shell (sh) and the Bourne-Again shell (bash).

While both of these shells have their features and capabilities, they can often be used interchangeably for many tasks.

In this article, I’ll compare sh vs bash to help you understand the differences between the two and determine which one might best fit your needs.

Overview of sh and bash

Before diving into the details of sh vs bash, let’s first look at each of these shells and how they came to be.

What is sh?

The Bourne shell, also known as sh, is a Unix shell developed by Steve Bourne in the late 1970s. It was the default shell on many Unix systems and is still widely used today.

The Bourne shell is known for its simplicity and ease of use, making it a popular choice for beginners and experts.

One of the critical features of the Bourne shell is its ability to execute commands stored in a script file, which can be used to automate tasks and streamline workflows.

The Bourne shell also supports variables, control structures (such as if/then statements), and functions, making it a powerful tool for writing scripts and programs.

What is bash?

The Bourne-Again shell, also known as bash, is a Unix shell that was developed as a free software replacement for the Bourne shell. It was created by Brian Fox in the late 1980s and has since become the default shell on many Linux and macOS systems.

Like the Bourne shell, bash is a powerful tool for running commands and automating tasks. It includes many of the same features as the Bourne shell, such as variables, control structures, and functions, but it also includes some additional features and enhancements.

One of the key differences between bash and the Bourne shell is the inclusion of command line editing, which allows users to edit and modify their commands before execution easily.

Bash also includes additional control structures, such as the case statement and support for arrays and string manipulation.

Related: How to Fix “-bash: ng: command not found”

Comparison of sh vs bash

Now that we have a basic understanding of sh and bash let’s take a closer look at some of the differences between the two shells.

Syntax and commands

One of the main differences between sh and bash is the syntax and commands used. While both shells support a similar set of basic commands, such as cd, ls, and echo, the syntax for these commands can vary slightly between the two.

For example, in sh, the if statement is written as follows:

if [ condition ] then command fi 

In contrast, the if statement in bash is written like this:

if [ condition ]; then command fi

Note that in bash, the then keyword is separated from the if statement by a semicolon, while in sh it is not. This is just one example of the minor differences in syntax between the two shells.

Built-in commands and functions

In addition to the differences in syntax, sh and bash also have some differences in their built-in commands and functions.

For example, bash includes some built-in commands and functions unavailable in sh. Some of these include:

  • history: This command allows you to view the history of previously entered commands.
  • alias: This command allows you to create aliases for other commands, making it easier to run frequently used commands.
  • type: This command allows you to determine the type of a command (e.g., built-in, alias, or external command).
  • source: This command allows you to execute a script file in the current shell environment rather than creating a new shell to run the script.

In addition to these commands, bash also includes support for arrays and string manipulation, which can be useful for advanced script writing.

Compatibility with other shells

Another factor to consider when comparing sh vs bash is compatibility with other shells.

In general, bash is more compatible with other shells than sh is. This is because bash is based on the Bourne shell and includes many of the same features, making it easier to port scripts between the two shells.

However, it’s worth noting that sh and bash are widely used and supported on various platforms, so compatibility may not be a major concern for many users.

Performance and speed

In terms of performance and speed, there is no significant difference between sh and bash. Both shells are designed to be fast and efficient and have optimization techniques to ensure they run smoothly.

That being said, it’s worth noting that bash may be slightly slower than sh due to its additional features and capabilities. However, the difference in performance is generally not noticeable unless you run extremely large scripts or programs.

Ease of use

One potential advantage of sh over bash is its simplicity and ease of use. As mentioned earlier, the Bourne shell is known for its simplicity, making it a popular choice for beginners just starting with shell scripting.

On the other hand, Bash includes a number of additional features and capabilities, which can make it somewhat more complex and harder to learn for beginners. However, once you become familiar with bash, it can be a powerful and efficient tool for many tasks.

sh vs bash: Which shell should you use?

So, which shell should you use: sh or bash? Ultimately, the choice will depend on your needs and preferences.

If you are starting with shell scripting and are looking for a simple and easy-to-use shell, sh may be the better choice. It is widely supported and is a solid choice for many tasks.

On the other hand, if you are an experienced developer looking for a more powerful and feature-rich shell, bash may be the better option. It includes many of the same features as sh, but several additional capabilities can be helpful for advanced scripting and automation.

Ultimately, the choice between sh and bash will depend on your specific needs and preferences. Both shells are widely used and supported, and they both have their strengths and weaknesses.

By understanding the differences between the two, you can make an informed decision about the best fit for your needs.

Related: Automation with Bash Scripts

Frequently Asked Questions

Is bash a superset of sh?

Bash is based on the Bourne shell and includes many of the same features and capabilities. However, it also includes several additional features and enhancements that are unavailable in sh.

As such, it is often referred to as a “superset” of the Bourne shell.

Can I use bash scripts with sh?

In general, bash scripts can be used with sh, but there may be some compatibility issues depending on the specific features and commands used in the script. For example, if the script uses bash-specific commands or features that are not available in sh, it may not run properly.

To ensure compatibility, it is generally recommended to use the #!/bin/bash shebang at the top of bash scripts rather than #!/bin/sh, which specifies that the script should be run with sh.

Can I use sh scripts with bash?

In general, sh scripts can be used with bash, but there may be some compatibility issues depending on the specific features and commands used in the script. For example, if the script uses sh-specific syntax not recognized by bash, it may not run properly.

To ensure compatibility, it is generally recommended to use the #!/bin/sh shebang at the top of sh scripts rather than #!/bin/bash, which specifies that the script should be run with bash.

Is sh or bash better for scripting?

Both sh and bash are powerful tools for scripting, and the choice between the two will depend on your specific needs and preferences.

If you are starting with shell scripting and are looking for a simple and easy-to-use shell, sh may be the better choice. It is widely supported and is a solid choice for many tasks.

On the other hand, if you are an experienced developer looking for a more powerful and feature-rich shell, bash may be the better option. It includes many of the same features as sh, but also includes some additional capabilities that can be useful for advanced scripting and automation.

Is sh or bash faster?

Generally, there is no significant difference in performance between sh and bash. Both shells are designed to be fast and efficient and have optimization techniques to ensure they run smoothly.

That being said, it’s worth noting that bash may be slightly slower than sh due to its additional features and capabilities. However, the difference in performance is generally not noticeable unless you run extensive scripts or programs.

Can I use sh and bash together?

Yes, using sh and bash together in a single script or program is possible. This can be useful if you want to take advantage of both shells’ specific features and capabilities.

To use sh and bash together in a single script, you can use the #!/bin/bash shebang at the top of the script to specify that it should be run with bash, and then use the sh command to execute specific commands or blocks of code with sh. For example:

#!/bin/bash # Some bash code sh <<EOF # Some sh code EOF # More bash code

By using this technique, you can mix and match the features and capabilities of both shells to suit your needs.

Tim Miller

Tim has always been obsessed with computers his whole life. After working for 25 years in the computer and electronics field, he now enjoys writing about computers to help others. Most of his time is spent in front of his computer or other technology to continue to learn more. He likes to try new things and keep up with the latest industry trends so he can share them with others.

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