diff options
Diffstat (limited to 'doc/stdenv.xml')
| -rw-r--r-- | doc/stdenv.xml | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/doc/stdenv.xml b/doc/stdenv.xml index 89589293844..434b61fd6a4 100644 --- a/doc/stdenv.xml +++ b/doc/stdenv.xml @@ -1169,7 +1169,17 @@ PATH=/nix/store/68afga4khv0w...-coreutils-6.12/bin echo @foo@ </programlisting> - That is, no substitution is performed for undefined variables.</para></listitem> + That is, no substitution is performed for undefined variables.</para> + + <para>Environment variables that start with an uppercase letter or an + underscore are filtered out, + to prevent global variables (like <literal>HOME</literal>) or private + variables (like <literal>__ETC_PROFILE_DONE</literal>) from accidentally + getting substituted. + The variables also have to be valid bash “names”, as + defined in the bash manpage (alphanumeric or <literal>_</literal>, + must not start with a number).</para> + </listitem> </varlistentry> |