Fix typos in the docs

doc/sparse.texi

@@ -218,12 +218,12 @@ The real name of the sparse file is stored in the variable
 variable @code{GNU.sparse.realsize}.
 
 The sparse map itself is stored in the file data block, preceding the actual
-file data.  It consists of a series of octal numbers of arbitrary length, delimited
+file data.  It consists of a series of decimal numbers delimited
 by newlines. The map is padded with nulls to the nearest block boundary.
 
-The first number gives the number of entries in the map. Following are map entries,
-each one consisting of two numbers giving the offset and size of the
-data block it describes.
+The first number gives the number of entries in the map. Following are
+map entries, each one consisting of two numbers giving the offset and
+size of the data block it describes.
 
 The format is designed in such a way that non-posix aware @command{tar}s and @command{tar}s not
 supporting @code{GNU.sparse.*} keywords will extract each sparse file

doc/tar.texi

@@ -5477,7 +5477,7 @@ reproducible archives given a common timestamp for generated files
 while still retaining the original timestamps of untouched files.
 
 @smallexample
-$ @kbd{tar -c -f archive.tar --clamp-mtime --mtime=@atchar{}$SOURCE_DATE_EPOCH .}
+$ @kbd{tar -c -f archive.tar --clamp-mtime --mtime=@@$SOURCE_DATE_EPOCH .}
 @end smallexample
 
 @item --owner=@var{user}