some documenation for download_file, TL_DOWNLOAD_PROGRAM and _ARGS

git-svn-id: svn://tug.org/texlive/trunk@7513 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 10 insertions, 1 deletions

diff --git a/Master/tlpkg/TeXLive/TLUtils.pm b/Master/tlpkg/TeXLive/TLUtils.pm
index 929681a69f5..d2d51ab402b 100644
--- a/Master/tlpkg/TeXLive/TLUtils.pm
+++ b/Master/tlpkg/TeXLive/TLUtils.pm
@@ -710,13 +710,22 @@ sub setup_programs {
 =item C<download_file( $path, $destination [, $progs ] )>
 
 Try to download the file given in C<$relpath> from either C<$TeXLiveURL>
-or C<TeXLiveAlternativeURL> into C<$destination> (a filename!). 
+or C<TeXLiveAlternativeURL> into C<$destination>, which can be either 
+a filename of simply C<|>. In the latter case a file handle is returned.
 
 The optional argument C<$progs> is a reference to a hash giving full pathes 
 to the respective programs, at least C<wget>. In case that C<$progs> is not
 given the C<%::progs> is consulted, and if this also does not exist we
 try "wget".
 
+Downloading honors two environment variables C<TL_DOWNLOAD_PROGRAM> and
+C<TL_DOWNLOAD_ARGS>. The former overrides C<wget> (or what is given in the
+C<$progs> argument, the latter overrides the default wget arguments
+given in C<$TeXLive::TLConfig::DefaultWgetArgs>. 
+
+C<TL_DOWNLOAD_ARGS> must be set up in a way that the place the output should
+go to is the first argument after the C<TL_DOWNLOAD_ARGS>. Use with care.
+
 =cut
 
 sub download_file {