ssss (separate standard streams)

This is to visually separate stdout and stderr by printing each with its own colour, or if colour isn't possible, then by prefixing each line with the file descriptor whence it came (1 for stdout, 2 for stderr). Running

$ ssss PROG

is a bit like

$ PROG > >(sed $'s/^/\e[32m/') 2> >(sed $'s/^/\e[31m/')

in GNU bash, and likewise

$ ssss -Cp PROG

is like

$ PROG > >(sed 's/^/\&1 /') 2> >(sed 's/^/\&2 /')

but hopefully less mank.

It sticks to low-level Unix functions, and is written in ANSI C; mostly requires only POSIX 1993 (with a couple widely available exceptions described in the source) and could hypothetically probably maybe compile on 4.3BSD, although I haven't tested that and wouldn't want to. It should almost certainly compile and run fine on any Unix-like system (except maybe some pure SysV derivatives like HP-UX or IBM AIX, if that's still around).

Building

To build, run make. If applicable, this will automatically run configure.sh to generate config.h (don't worry, it's not an autoconf script). ssss depends only on ANSI C and a POSIX-conformant standard C library; it should build straight away on any modern unix-like system.

make all or make doc builds a manual page -- this requires GNU help2man, a perl script, available at https://ftpmirror.gnu.org/help2man and on most package managers.

The -S switch requires wide-character support from C95. There is currently no way to disable this, as I've personally never even seen a pre-C95 toolchain, but it should be fairly trivial to implement if for some reason it becomes necessary (famous last words).

For usage, run it with -h or --help, or see the generated ssss.1 manpage if available. For more information about system compatibility and dependencies, see comments in the source (near the top) and configure.sh, and if you really need that then godspeed to you.

Copyright

Copyright © 2023-2024 The Remph [email protected]. This is free software: file-specific licence information is contained in SPDX headers at the top of each file, and the full GPL text is in the file GPL, or at https://gnu.org/licenses/gpl.txt.

BUGS

• Small caveat to ANSI C (ie. C89) conformance: the help message is a bit longer than the minimum required string length of an ANSI C compiler (509 bytes), but if you're using a very strictly ANSI C-compliant compiler with a hard 509-byte string cutoff, you probably have bigger problems

• If the child process (PROG in -h output) exits quickly, its output may be flushed to us all at once, which means the output of each stream at the time of flushing will be printed each in one block per stream rather than in the order it was written. For example (with possible not certain outputs; can be influenced by timing and kernel caching for instance):

  $ ssss -p sh -c 'echo foo; echo bar >&2; echo yeedleyeedleyee'
  &2 bar
  &1 foo
  &1 yeedleyeedleyee
  $ rlwrap -AS $'\e[36m> ' ssss -p sh
  > echo foo; echo bar >&2; echo yeedleyeedleyee
  &1 foo
  &2 bar
  &1 yeedleyeedleyee
  

  As of commit f33db16e this behaviour is fairly sporadic.