(this means variable expansion is explicitly not
supported), allowing applications to read the file
without implementing a shell compatible execution
- engine. Variable assignment values should be enclosed
- in double or single quotes if they include spaces,
+ engine. Variable assignment values must be enclosed in
+ double or single quotes if they include spaces,
semicolons or other special characters outside of A-Z,
- a-z, 0-9. All strings should be in UTF-8 format, and
- non-printable characters should not be used. If double
- or single quotes or backslashes are to be used within
- variable assignments, they should be escaped with
- backslashes, following shell style. It is not
- supported to concatenate multiple individually quoted
- strings. Lines beginning with "#" shall be ignored as
- comments.</para>
+ a-z, 0-9. Shell special characters ("$", quotes,
+ backslash, backtick) must be escaped with backslashes,
+ following shell style. All strings should be in UTF-8
+ format, and non-printable characters should not be used.
+ It is not supported to concatenate multiple individually
+ quoted strings. Lines beginning with "#" shall be
+ ignored as comments.</para>
<para>The file <filename>/etc/os-release</filename>
takes precedence over
files at the same
time. <filename>/usr/lib/os-release</filename> is the
recommended place to store OS release information as
- part of vendor trees. Frequently,
- <filename>/etc/os-release</filename> is simply a
- symlink to <filename>/usr/lib/os-release</filename>,
+ part of vendor trees.
+ <filename>/etc/os-release</filename> should be a
+ relative symlink to
+ <filename>/usr/lib/os-release</filename>,
to provide compatibility with applications only
- looking at <filename>/etc</filename>.</para>
+ looking at <filename>/etc</filename>. A relative
+ symlink instead of an absolute symlink is
+ necessary to avoid breaking the link in a chroot or
+ initrd environment such as dracut.</para>
<para><filename>os-release</filename> contains data
that is defined by the operating system vendor and