Cygwin BASH and ANSI control sequences

Question

Several things here:

1. Can anyone point me at C code to decode ANSI console escape sequences?
2. Is there a way to get Cygwin BASH to emulate a dumb old TTY?

Maybe this should be 2 questions.

Thanks.

Kelsy

You mean act on ANSI escape sequences? Like move the cursor? – Ovarian

What do you mean by "Get Cygwin BASH to emulate a dumb old TTY"? Bash is a a shell; it is not a terminal emulator. – Poston

Answer 1

It's a somewhat indirect answer, but the GNU ncurses library handles terminals of all sorts. One way of finding out which control sequences are applicable to ANSI terminals would be to decompile an ANSI terminal description:

infocmp ansi

This would give you the set of terminfo attributes that are used by curses programs to achieve effects on an ANSI terminal. Of course, you then have to know what those hieroglyphs mean.

On Cygwin, I got:

$ infocmp ansi
#       Reconstructed via infocmp from file: /usr/share/terminfo/61/ansi
ansi|ansi/pc-term compatible with color,
    am, mc5i, mir, msgr,
    colors#8, cols#80, it#8, lines#24, ncv#3, pairs#64,
    acsc=+\020\,\021\030.^Y0\333`\004a\261f\370g\361h\260j\331k\277l\332m\300n\305o~p\304q\304r\304s_t\303u\264v\301w\302x\263y\363z\362{\343|\330}\234~\376,
    bel=^G, blink=\E[5m, bold=\E[1m, cbt=\E[Z, clear=\E[H\E[J,
    cr=^M, cub=\E[%p1%dD, cub1=\E[D, cud=\E[%p1%dB, cud1=\E[B,
    cuf=\E[%p1%dC, cuf1=\E[C, cup=\E[%i%p1%d;%p2%dH,
    cuu=\E[%p1%dA, cuu1=\E[A, dch=\E[%p1%dP, dch1=\E[P,
    dl=\E[%p1%dM, dl1=\E[M, ech=\E[%p1%dX, ed=\E[J, el=\E[K,
    el1=\E[1K, home=\E[H, hpa=\E[%i%p1%dG, ht=\E[I, hts=\EH,
    ich=\E[%p1%d@, il=\E[%p1%dL, il1=\E[L, ind=^J,
    indn=\E[%p1%dS, invis=\E[8m, kbs=^H, kcbt=\E[Z, kcub1=\E[D,
    kcud1=\E[B, kcuf1=\E[C, kcuu1=\E[A, khome=\E[H, kich1=\E[L,
    mc4=\E[4i, mc5=\E[5i, nel=\r\E[S, op=\E[39;49m,
    rep=%p1%c\E[%p2%{1}%-%db, rev=\E[7m, rin=\E[%p1%dT,
    rmacs=\E[10m, rmpch=\E[10m, rmso=\E[m, rmul=\E[m,
    s0ds=\E(B, s1ds=\E)B, s2ds=\E*B, s3ds=\E+B,
    setab=\E[4%p1%dm, setaf=\E[3%p1%dm,
    sgr=\E[0;10%?%p1%t;7%;%?%p2%t;4%;%?%p3%t;7%;%?%p4%t;5%;%?%p6%t;1%;%?%p7%t;8%;%?%p9%t;11%;m,
    sgr0=\E[0;10m, smacs=\E[11m, smpch=\E[11m, smso=\E[7m,
    smul=\E[4m, tbc=\E[3g, u6=\E[%i%d;%dR, u7=\E[6n,
    u8=\E[?%[;0123456789]c, u9=\E[c, vpa=\E[%i%p1%dd,

$

The '\E' notation refers to the ESC character.

Failing that, you could look up the standard itself.

Poston

Thanks. Yes I got hold of some ANSI emulator code. The thing is that when Cygwin BASH is running it appears to send strange control sequences, notably \E]0 ... which is definitely not in the standard! The rest is all color control info. – Kelsy

Answer 2

Tweaking the TERM environment variable might make applications based on terminfo/termcap avoid using advanced escape sequences. (export TERM=dumb) I am not sure that's what you want, though.

Natality