X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=select.ggo;h=d02fcd39112745d7d9f86f5be48113343ae54b60;hb=36aa5262a8454139eee6622841ac0176b0e4fb15;hp=5ea4e8e80825ef0193c0e69e02c9341f07683fd7;hpb=26ace9b8c1dc872e5da1b1122b45f01419761aab;p=adu.git

diff --git a/select.ggo b/select.ggo
index 5ea4e8e..d02fcd3 100644
--- a/select.ggo
+++ b/select.ggo
@@ -83,11 +83,32 @@ details="
 option "output" o
 #~~~~~~~~~~~~~~~~
 "file to write output to"
-string typestr="<path>"
+string typestr="path"
 optional
 default="-"
 details="
-	If empty, or not given, use stdout.
+	If empty, or not given, use stdout. The following conventions
+	cause the output to be written differently:
+
+	An output file name of \"-\" means stdout.
+
+	\"path\" may be prepended by '>' which instructs adu to
+	truncate the output file to length zero.  If \"path\" does
+	not start with '>' and \"path\" already exists, the select
+	query is being aborted. Otherwise, \"path\" is created and
+	output is written to \"path\".
+
+	If the first two characters of \"path\" are '>', the output
+	file (given by removing the leading \">>\" from \"path\")
+	is being opened in append mode. It is no error if the output
+	file does not exist but, as above, the output file name \">>\"
+	is considered invalid.
+
+	If the first character of \"path\" is '|', a pipe is created
+	and the rest of \"path\" is being executed with its standard in
+	redirected to the reading end of the pipe. The output of adu
+	is written to the writing end of the pipe. Again, specifying
+	only \"|\" is considered invalid and causes an error.
 "
 
 option "user-summary-sort" -