JimK wrote: > I have written a java applet to interact with bash in the background to let > the applet user interact just like they were using bash itself.
Does this java applet set up a master-slave pty for bash's input and output? This is what the 'expect' program and similar usually do. > But when the initial output from bash comes to my applet, it says "bash: no > job control in this shell". When bash starts up it inspects the stdin (IIRC) and determines that it either is or is not a tty device. If a tty then it assumes it is running interactively. If not a tty then it behaves in a batch mode. I did not remember bash using this to enable/disable job control but bash does use this to affect an 'interactive' mode enabled/disabled and that does have other effects such as printing of prompts and other things. > Which initially I didn't think really mattered, but I just found out that > man/less/more do not work after displaying their initial screen. Commands > like "q" are not processed like they should so you are stuck inside of > man/less/more. You would probably need "q\n" in order to get the data flushed to the subprocess. This is probably a stdio buffering issue. When the stdio library determines that the output is not a tty then the output is buffered into large blocks for performance reasons. If the output is a tty then buffering is disabled. (I can't remember if buffering is off or line buffered when the output is a tty.) > So I am wondering if it is because I do not have any job control in my > shell. No. But it is related to the same reason that job control is not enabled. > So, I am trying to find out why my bash has no job control and how I can > address that to see if that is why man/less/more do not work. Because pagers routinely place the tty into raw mode and also control the full screen they usually expect a full terminal environment including tty and terminal emulation. When this is not available they fall back into a line oriented operating mode. When the tty driver is in the standard canonical mode a newline is usually required to enter data. If no tty driver is present then it won't be used and can't be placed into a raw mode. Then standard program buffering rules apply. > Appreciate any insights as to why bash is deciding it has no job control or > how I might find out why it is saying that .. Look at the 'expect' program as one example well known for handling subprocesses in this way. Bob _______________________________________________ Bug-bash mailing list Bug-bash@gnu.org http://lists.gnu.org/mailman/listinfo/bug-bash
