s6-linux-init: the s6-linux-init-echo program
Keywords: s6-linux-init command s6-linux-init-echo echo

s6-linux-init
Software
skarnet.org

# The `s6-linux-init-echo` program

s6-linux-init-echo writes its arguments to stdout.

## Interface

         s6-linux-init-echo [ -n ] [ -s sep ] args...

s6-linux-init-echo writes its arguments args to stdout, separated with spaces.

## Options

- `-n` : do not output a trailing newline.
- `-s` sep : separate arguments with the sep character instead of a space.

## Notes

- Strange, and appalling, as it may seem for such a simple task, there is no way to ensure that the `echo` program will behave consistently from Unix system to Unix system - and even from Linux distribution to Linux distribution. Despite there being a standard for it, the `echo` commands in GNU coreutils, busybox, toybox, sbase, and other implementations basically all exhibit different behaviours. Every shell has a built-in `echo` command, that fails to follow the POSIX standard. `echo` is the prime example of the consequences of the blatant disregard of early Unices for cross-system compatibility, and its followup as a turf war between GNU and the rest of the Linux world. As a distribution-agnostic software developer, it is ironically impossible to rely on a definite behaviour of the `echo` command on every supported system, and that is why s6-linux-init provides its own implementation. Fortunately, it is very easy to do so, with minimal overhead.
- This command is an exact duplicate of the s6-echo command provided in the s6-portable-utils package. It was decided not to have a dependency from s6-linux-init to s6-portable-utils: that dependency would arguably be a higher cost than the small amount of code duplication.