# echo

_Peios / Using Peios / Peiosutils / Output and evaluation_

> Print arguments as a line of text to standard output.

`echo` prints its arguments, separated by single spaces, followed by a newline.

```
echo [options] [string...]
```

```
$ echo Hello, Peios
Hello, Peios
```

It is the simplest way to put a line of text on standard output — printing a message, or feeding a fixed string into a pipe.

## Options

| Option | Effect |
|---|---|
| `-n` | Do not print the trailing newline. |
| `-e` | Interpret backslash escape sequences in the arguments (see below). |
| `-E` | Do **not** interpret escape sequences. This is the default. |

## Escape sequences

With `-e`, `echo` recognises these backslash sequences and prints the character they stand for:

| Sequence | Character |
|---|---|
| `\\` | A literal backslash. |
| `\n` | Newline. |
| `\t` | Horizontal tab. |
| `\r` | Carriage return. |
| `\b` | Backspace. |
| `\f` | Form feed. |
| `\v` | Vertical tab. |
| `\a` | Alert (the terminal bell). |
| `\e` | Escape. |
| `\0NNN` | The byte with octal value `NNN`. |
| `\xHH` | The byte with hexadecimal value `HH`. |
| `\c` | Stop — produce no further output. |

## `echo` and `printf`

`echo` is fixed: arguments, spaces, a newline. The moment you need *control* over the output — columns, padding, a number formatted a particular way, output with no spaces between pieces — use [`printf`](/peios/using-peios/peiosutils/output-and-evaluation/printf.md) instead. `printf` is also more predictable across environments, since `echo`'s handling of escapes and `-n` varies.

## A note on shells

Many command shells provide their own built-in `echo`, and the shell's version is what runs when you type `echo` at a prompt. Built-in versions vary — especially in how they treat `-n`, `-e`, and escape sequences — so their behaviour may differ from what is described here. To be certain you are running this command rather than the shell built-in, invoke it by its full path.

## Exit status

| Code | Meaning |
|---|---|
| `0` | The output was written. |
| `1` | The output could not be written. |

Related content:

- [printf](/peios/using-peios/peiosutils/output-and-evaluation/printf.md)
- [Output and evaluation](/peios/using-peios/peiosutils/output-and-evaluation/overview.md)