It is a command available in various operating system shells and typically used in shell scripts and batch files to output status text to the screen[1] or a computer file, or as a source part of a pipeline.

After it was programmed in C by Doug McIlroy as a "finger exercise" and proved to be useful, it became part of Version 2 Unix.

[20] Nowadays, several incompatible implementations of echo exist on different operating systems (often several on the same system), some of them expanding escape sequences by default, some of them not, some of them accepting options (the list of which varying with implementations), some of them not.

The POSIX specification of echo[21] leaves the behaviour unspecified if the first argument is -n or any argument contain backslash characters while the Unix specification (XSI option in POSIX) mandates the expansion of (some) sequences and does not allow any option processing.

Using ANSI escape code SGR sequences, compatible terminals can print out colored text.