Add an example to README.

[adu.git] / select.ggo

diff --git a/select.ggo b/select.ggo
index 140311b8349cf3c91f23d5026d9a5e8bfcd58b03..e2c91f8f76eb2f999898aeaca760acff37d891c6 100644 (file)
--- a/select.ggo
+++ b/select.ggo
@@ -87,6 +87,20 @@ details="
        output to scripts.
 "
 
+option "trailer" T
+#~~~~~~~~~~~~~~~~~
+"use a customized trailer for listings/summaries"
+string typestr="string"
+optional
+default=""
+details="
+       This option can be used to print any string at the end of
+       the query output.
+
+       In user_list mode the trailer is a format string with the
+       same semantics like the header string.
+"
+
 option "select-mode" m
 #~~~~~~~~~~~~~~~~~~~~~
 "How to print the results of the query"
@@ -116,11 +130,32 @@ 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" -