Introduction

Have you ever found yourself wondering which command is best to use when printing output in a shell script? Do you use echo or printf? Or do you use both interchangeably without really thinking about it?

Well, it’s time to settle the debate once and for all. In this blog, we’ll explore the differences between echo and printf, and provide some tips on when to use each one.

The Basics

echo and printf are both commands that are used to print output in a shell script. They both have their own set of options and capabilities, which we’ll discuss in more detail later on.

Here’s an example of how echo is used:

echo "Hello, world!"

And here’s an example of how printf is used:

printf "Hello, world!"\\n

As you can see, the syntax for each command is slightly different. echo simply takes a string as its argument, while printf requires a format string and a list of arguments to fill in the placeholders in the format string.

The Surprising Fact

Here’s a surprising fact: echo is actually a shell builtin, not a separate command. This means that it is implemented directly in the shell itself, rather than being an external program that is called by the shell. On the other hand, printf is an external command that is provided by the coreutils package.

This has a few implications. First, echo is generally faster than printf because it doesn’t have the overhead of starting an external process. Second, the behavior of echo can vary slightly between different shells, while printf is more standardized.

When to Use echo

So when should you use echo? Here are a few tips:

1. If you just need to print a simple string with no formatting, echo is a good choice.
2. If you’re writing a script that needs to run quickly, echo may be faster due to its builtin nature.
3. If you’re writing a script that needs to be portable across different shells, echo is a safer choice because its behavior is more consistent.

Here’s an example of how echo might be used in a script for the website itvraag.nl:

# Print the number of articles on itvraag.nl
ARTICLE_COUNT=$(curl -s <https://www.itvraag.nl> | grep -c 'article-title')
echo "There are currently $ARTICLE_COUNT articles on itvraag.nl."

When to Use printf

Now let’s talk about when to use printf. Here are a few tips:

1. If you need to format the output with placeholders and arguments, printf is the way to go.
2. If you need to print special characters that may be interpreted differently by echo, such as backslashes or escape sequences, printf is a safer choice.
3. If you need to print a string that contains variables or command substitutions, printf is a better choice because it allows you to specify the format of the output more precisely.

Here’s an example of how printf might be used in a script for itvraag.nl:

# Print the top articles on itvraag.nl
TOP_ARTICLES=$(curl -s <https://www.itvraag.nl/top-articles>)
printf "Top articles on itvraag.nl:\\n%s\\n" "$TOP_ARTICLES"

Key Takeaways

To summarize, here are the key takeaways from this blog:

1. echo is a shell builtin while printf is an external command.
2. echo is generally faster than printf, but its behavior can vary between shells.
3. echo is a good choice for simple string printing with no formatting, while printf is better for formatting and special characters.
4. printf is a safer choice for printing strings with variables or command substitutions.

Tips for Increased Productivity

Now that you know the differences between echo and printf, how can you apply this knowledge to increase your productivity? Here are five tips:

1. Use echo for simple string printing with no formatting. This will save you time and make your scripts more readable.
2. Use printf when you need to format the output with placeholders and arguments. This will give you more control over the appearance of the output.
3. Use printf when you need to print special characters that may be interpreted differently by echo. This will prevent issues with unexpected behavior.
4. Use printf when you need to print a string that contains variables or command substitutions. This will ensure that the output is displayed correctly.
5. Familiarize yourself with the options and capabilities of both echo and printf, so that you can choose the best tool for the job.

Challenge

Now it’s your turn to put your newfound knowledge to the test. Here’s a challenge for you:

Write a shell script that prints a table of the numbers 1 to 10, with the number and its square on each line. The table should be aligned and formatted using printf.

Here’s an example of what the output should look like:

Number  Square
1       1
2       4
3       9
4       16
5       25
6       36
7       49
8       64
9       81
10      100

Can you write a script that produces this output? Give it a try, and see how printf can be used to format and align the output.