In general, new non-standard options are bad.
Basically, if we add this someone will use it in a script. Then it will
become non-portable. You cannot just invent something on your own like
this, without doing research to find out if someone else added a different
option. I don't see evidence of that, so the gut answer is no.
> here is a diff that adds optional linebuffering to tr(1) with command
> line switch -u like in sed(1). I need this to remove '\r' characters
> from a continues input steam which lines have to be there immediately.
>
> Please write me if something is wrong with this diff or the change
> itself. I will fix it.
>
> bye,
> Jan
>
> Index: tr.1
> ===================================================================
> RCS file: /cvs/src/usr.bin/tr/tr.1,v
> retrieving revision 1.20
> diff -u -p -r1.20 tr.1
> --- tr.1 14 Aug 2013 08:39:27 -0000 1.20
> +++ tr.1 19 Nov 2013 20:46:33 -0000
> @@ -41,18 +41,18 @@
> .Nd translate characters
> .Sh SYNOPSIS
> .Nm tr
> -.Op Fl cs
> +.Op Fl csu
> .Ar string1 string2
> .Nm tr
> -.Op Fl c
> +.Op Fl cu
> .Fl d
> .Ar string1
> .Nm tr
> -.Op Fl c
> +.Op Fl cu
> .Fl s
> .Ar string1
> .Nm tr
> -.Op Fl c
> +.Op Fl cu
> .Fl ds
> .Ar string1 string2
> .Sh DESCRIPTION
> @@ -86,6 +86,14 @@ or
> .Ar string2 )
> in the input into a single instance of the character.
> This occurs after all deletion and translation is completed.
> +.It Fl u
> +Force output to be line buffered,
> +printing each line as it becomes available.
> +By default, output is line buffered when standard output is a terminal
> +and block buffered otherwise.
> +See
> +.Xr setbuf 3
> +for a more detailed explanation.
> .El
> .Pp
> In the first synopsis form, the characters in
> @@ -284,6 +292,10 @@ The
> utility is compliant with the
> .St -p1003.1-2008
> specification.
> +.Pp
> +The flag
> +.Op Fl u
> +is an extension to that specification.
> .Pp
> System V has historically implemented character ranges using the syntax
> .Dq [c-c]
> Index: tr.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/tr/tr.c,v
> retrieving revision 1.15
> diff -u -p -r1.15 tr.c
> --- tr.c 27 Oct 2009 23:59:46 -0000 1.15
> +++ tr.c 19 Nov 2013 20:46:33 -0000
> @@ -88,7 +88,7 @@ main(int argc, char *argv[])
> int cflag, dflag, sflag, isstring2;
>
> cflag = dflag = sflag = 0;
> - while ((ch = getopt(argc, argv, "cds")) != -1)
> + while ((ch = getopt(argc, argv, "cdsu")) != -1)
> switch((char)ch) {
> case 'c':
> cflag = 1;
> @@ -99,6 +99,9 @@ main(int argc, char *argv[])
> case 's':
> sflag = 1;
> break;
> + case 'u':
> + setlinebuf(stdout);
> + break;
> case '?':
> default:
> usage();
> @@ -239,9 +242,9 @@ static void
> usage(void)
> {
> fprintf(stderr,
> - "usage: tr [-cs] string1 string2\n"
> - " tr [-c] -d string1\n"
> - " tr [-c] -s string1\n"
> - " tr [-c] -ds string1 string2\n");
> + "usage: tr [-csu] string1 string2\n"
> + " tr [-cu] -d string1\n"
> + " tr [-cu] -s string1\n"
> + " tr [-cu] -ds string1 string2\n");
> exit(1);
> }
>
