doc: usage: Add general rule for $?

For nearly all commands in U-Boot the '?' variable is handled the same
way with 0 meaning success, 1 meaning any failure.  Explain this in the
general rules section of the cmdline documentation (with a link to a
counter example) and then remove the redundant wording from most
commands. We retain a section about the return value in a number of
places where we are doing something such as always returning a specific
value or we have useful additional information to go along with the
normal return codes.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
This commit is contained in:
Tom Rini
2025-10-24 10:02:57 -06:00
parent 1f6da608c3
commit 11da3403e9
45 changed files with 6 additions and 245 deletions

View File

@@ -188,9 +188,3 @@ The FIT image file format requires CONFIG_FIT=y.#
The legacy U-Boot image file format requires CONFIG_LEGACY_IMAGE_FORMAT=y.
On hardened systems support for the legacy U-Boot image format should be
disabled as these images cannot be signed and verified.
Return value
------------
If the scripts is executed successfully, the return value $? is 0 (true).
Otherwise it is 1 (false).