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In Unix-like systems, printf is a POSIX-standard command for producing formatted output in the terminal. Unlike echo, which is usually a shell builtin, printf is an external executable that you invoke each time – trading a slight performance cost for precise control over formatting, field widths, alignment, and escape sequences.

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echo vs printf

When you run echo, the shell handles it internally: 
$ echo "Hello, world!"
Hello, world!
By contrast, printf is an external program: 
$ printf "Hello, printf!\n"
Hello, printf!
Because printf is external, the shell forks a new process to execute it. Despite this overhead, printf offers richer formatting capabilities and consistent behavior across different shells.
The image shows a diagram related to the "printf" function, highlighting its capabilities such as formatting text in a specific way, left-aligning, and right-aligning.

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Format Specifiers

printf uses format specifiers similar to C’s printf(). Here are the most common ones:
SpecifierDescriptionExample
%sStringprintf "%s\n" "text"
%dSigned integerprintf "%d\n" 42
%fFloating-point numberprintf "%.2f\n" 3.14159
%oOctal representationprintf "%o\n" 10
%x/%%XHexadecimal (lowercase/uppercase)printf "%x\n" 255
%%Literal percent signprintf "%%\n"

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Example: Strings and Numbers

#!/usr/bin/env bash
course="Advanced Shell Scripting"
printf "Welcome to the %s\n" "$course"

name="Alice"
age=28
weight=65.2
printf "Name: %s | Age: %d | Weight: %.1f kg\n" \
    "$name" "$age" "$weight"
This prints: 
Welcome to the Advanced Shell Scripting
Name: Alice | Age: 28 | Weight: 65.2 kg
The image shows a dark background with four dotted boxes labeled "Floating numbers," "Width for integers," "Alignment," and "...", under the title "printf."

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Escape Sequences and Portability

Different shells handle echo escape sequences inconsistently. For example: 
$ echo "Line1\nLine2"
Line1\nLine2
$ echo -e "Line1\nLine2"
Line1
Line2
To ensure portability, use printf which interprets \n, \t, and other escapes by default: 
$ printf "Line 1\nLine 2\n"
Line 1
Line 2
Avoid relying on echo -e for escape handling across scripts. Use printf for consistent results in Bash, Dash, Zsh, and other POSIX-compliant shells.

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Return Status and Character Count

printf returns an exit status (0 on success) and you can pipe its output to wc -c to count characters: 
#!/usr/bin/env bash
message="Hello, world!"
if printf "%s" "$message"; then
    count=$(printf "%s" "$message" | wc -c)
    echo -e "\nPrinted $count characters successfully."
else
    echo "Error: printf failed with code $?"
fi

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References

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