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echo ⚬ˢʰ｜Definition｜1st｜20260523112531-00-⌔

echo (command) - Wikipedia

echo (command)

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echo is a shell command that writes input text to standard output. It is available in many operating system and shells. It is often used in a shell script to log status, provide feedback to the user and for debugging. For an interactive session, output by default displays on the terminal screen, but output can be re-directed to a file or piped to another process.1

Many shells implement echo as a builtin command rather than an external application as are many other commands.

Multiple, incompatible implementations of echo exist in different shells. Some expand escape sequences by default, and some do not. Some accept options, and some do not. The POSIX specification2 leaves the behavior unspecified if the first argument is -n or any argument contains backslash characters while the Unix specification (XSI option in POSIX) mandates the expansion of some sequences and does not allow any option processing. In practice, many echo implementations are not compliant in the default environment. Because of these variations, echo is considered a non-portable command3 and the printf command (introduced in Ninth Edition Unix) is preferred instead.

Printed 2026-06-29.

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Footnotes

  1. Rügheimer, Hannes; Spanik, Christian (September 12, 1988). AmigaDOS quick reference. Grand Rapids, Mi: Abacus. ISBN 9781557550491 – via Internet Archive. ↩

  2. echo: write arguments to standard output – Shell and Utilities Reference, The Single UNIX Specification, Version 5 from The Open Group ↩

  3. “Autoconf documentation on echo portability”. Free Software Foundation. Archived from the original on 10 December 2019. Retrieved 24 July 2016. ↩

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echo ⚬ˢʰ｜docu｜1st｜20251021001049-00-◊

echo(1) - Linux manual page
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