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Top Forums Shell Programming and Scripting In ksh, how does an in-line child sub-process get its own PID? Post 302074905 by matrixmadhan on Saturday 27th of May 2006 08:02:36 AM
Old 05-27-2006
Quote:
Anyway, I thought of a way to do it...I think. Background the subshell. Have the parent obtain $! and send it into the subshell via a named pipe. Then the parent waits for the subshell to exit.
if the subshell that is spawned is sent to the background process group,
there are subtle points to be noted:::

if the subshell is interactive one and if it has to be switched to foreground process group and that must be explicitly done by the parent and it cannot do that by itself; only thing that could be done by the child itself is being stopped by generating SIGTTIN/SIGTTOU

if the subshell is non-interactive, care must be taken that the subshell should not support any of the job control activities.
 

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line(1) 						      General Commands Manual							   line(1)

NAME
line - Reads one line from standard input SYNOPSIS
line STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: line: XCU5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. OPTIONS
None DESCRIPTION
The line command copies one line, up to and including a newline, from standard input and writes it to standard output. Use this command within a shell command file to read from your terminal. The line command always writes at least a newline character. NOTES
The line utility has no internationalization features and is marked LEGACY in XCU Issue 5. Use the read utility instead. EXIT STATUS
Success. End-of-File. EXAMPLES
To read a line from the keyboard and append it to a file, enter: echo 'Enter comments for the log:' echo ': c' line >>log This shell procedure displays the message: Enter comments for the log: It then reads a line of text from the keyboard and adds it to the end of the file log. The echo ': c' command displays a : (colon) prompt. See the echo command for information about the c escape sequence. SEE ALSO
Commands: echo(1), ksh(1), read(1), Bourne shell sh(1b), POSIX shell sh(1p) Functions: read(2) Standards: standards(5) line(1)
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