s6-portable-utils
Software
skarnet.org
 The s6-format-filter program 
s6-format-filter processes lines according to its arguments, and
prints the result.
 Interface 
     s6-format-filter format [ args... ]
 -  format is a format string that can contain the following special sequences:
%%, %s, and %0 to %9. 
-  For every line it reads on stdin, s6-format-filter prints format on
stdout, replacing %% with %, %0 with the command name
(probably s6-format-filter), %1 to %9 with the first
to the ninth argument in args, and %s with the input line. 
-  s6-format-filter exits 0 when it reads EOF.