DOC HOME SITE MAP MAN PAGES GNU INFO SEARCH
 

(diff.info.gz) Standards conformance

Info Catalog (diff.info.gz) Invoking sdiff (diff.info.gz) Top (diff.info.gz) Projects
 
 Standards conformance
 *********************
 
    In a few cases, the GNU utilities' default behavior is incompatible
 with the POSIX standard.  To suppress these incompatibilities, define
 the `POSIXLY_CORRECT' environment variable.  Unless you are checking
 for POSIX conformance, you probably do not need to define
 `POSIXLY_CORRECT'.
 
    Normally options and operands can appear in any order, and programs
 act as if all the options appear before any operands.  For example,
 `diff lao tzu -C 2' acts like `diff -C 2 lao tzu', since `2' is an
 option-argument of `-C'.  However, if the `POSIXLY_CORRECT' environment
 variable is set, options must appear before operands, unless otherwise
 specified for a particular command.
 
    Newer versions of POSIX are occasionally incompatible with older
 versions.  For example, older versions of POSIX allowed the command
 `diff -c -10' to have the same meaning as `diff -C 10', but POSIX
 1003.1-2001 `diff' no longer allows digit-string options like `-10'.
 
    The GNU utilities normally conform to the version of POSIX that is
 standard for your system.  To cause them to conform to a different
 version of POSIX, define the `_POSIX2_VERSION' environment variable to
 a value of the form YYYYMM specifying the year and month the standard
 was adopted.  Two values are currently supported for `_POSIX2_VERSION':
 `199209' stands for POSIX 1003.2-1992, and `200112' stands for POSIX
 1003.1-2001.  For example, if you are running older software that
 assumes an older version of POSIX and uses `diff -c -10', you can work
 around the compatibility problems by setting `_POSIX2_VERSION=199209'
 in your environment.
 
Info Catalog (diff.info.gz) Invoking sdiff (diff.info.gz) Top (diff.info.gz) Projects
automatically generated byinfo2html