In one window I just did:
It hung just as it should. In a second window I did echo hello > xyz and now the first window looks like:
(Except that I added red tags to show the new lines.)
Hi
I have a shell script A which calls another 10 shell scripts which run in background. How do i make the parent script wait for the child scripts complete, or in other words, i must be able to do a grep of parent script to find out if the child scripts are still running.
My Code:
... (1 Reply)
Hi All,
I will be glad if you could help me resolve this problem.
I have created two detachable threads and wanted to them execute independent of the parent thread ( the main task which creates the detachable threads). But I see no output coming from the execution of two detachable threads.... (4 Replies)
Hi All,
I have two ksh script. 1st script calls the 2nd script and the second script calls an 'C' program.
I want 1st script to wait until the 'C' program completes.
I cant able to get the process id for the 'C' program (child process) to make the 1st script to wait for the second... (7 Replies)
Hi All,
I facing a problem in handling signals between parent process communication. I am trying to send a signal(SIGINT) from child to parent. I am using kill function to do so and I am trying to read the signal using sigaction(). But the program is ending abruptly and I am not able to figure out... (4 Replies)
Hi, i want that the parent process start before the child, this code doesn't work,
if the child start before the parent it wait for signal, then the father send the signal SIGALRM and the child catch it and call printf;
else the father call printf and send the signal to the child that call its... (1 Reply)
1. The problem statement, all variables and given/known data:
I need to make an program that in a loop creates one parent and five children with fork(). The problem i'm trying to solve is how to delete the parent and child of the childīs process.
2. Relevant commands, code, scripts,... (0 Replies)
Hello, everyone.
Here's a program:
pid_t pid = fork();
if (0 == pid) // child process
{
execvp ...;
}
I send a signal (such as SIGINT) to the parent process, the child process receive the signal as well as the parent process.
However I don't want to child process to receive the... (7 Replies)
Hi everyone
i am very new to linux , working on bash shell.
I am trying to solve the given problem
1. Create a process and then create children using fork
2. Check the Status of the application for successful running.
3. Kill all the process(threads) except parent and first child... (2 Replies)
I have two scripts lets say A.expect and B.sh needs to be executed.
I am executing B.sh from A.expect where B.sh has sleep command.
My problem is that when B.sh encounters the sleep command my A.expect starts executing and exits.
but my A.expect should execute only after completing B.sh.
Is... (3 Replies)
Hi all,
I am starting mgen5 for sometime depends on input from a file, in a child process. now I want to make parent to wait in this child process till mgen5 finishes, or timeout happens.
could anyone please tell me how to make parent to wait in child process in shell script?
thanks... (2 Replies)
Discussion started by: girijajoshi
2 Replies
LEARN ABOUT OPENDARWIN
subst
subst(n) Tcl Built-In Commands subst(n)
__________________________________________________________________________________________________________________________________________________NAME
subst - Perform backslash, command, and variable substitutions
SYNOPSIS
subst ?-nobackslashes? ?-nocommands? ?-novariables? string
_________________________________________________________________DESCRIPTION
This command performs variable substitutions, command substitutions, and backslash substitutions on its string argument and returns the
fully-substituted result. The substitutions are performed in exactly the same way as for Tcl commands. As a result, the string argument
is actually substituted twice, once by the Tcl parser in the usual fashion for Tcl commands, and again by the subst command.
If any of the -nobackslashes, -nocommands, or -novariables are specified, then the corresponding substitutions are not performed. For
example, if -nocommands is specified, command substitution is not performed: open and close brackets are treated as ordinary characters
with no special interpretation.
Note that the substitution of one kind can include substitution of other kinds. For example, even when the -novariables option is speci- |
fied, command substitution is performed without restriction. This means that any variable substitution necessary to complete the command |
substitution will still take place. Likewise, any command substitution necessary to complete a variable substitution will take place, even |
when -nocommands is specified. See the EXAMPLES below. |
If an error occurs during substitution, then subst will return that error. If a break exception occurs during command or variable substi- |
tution, the result of the whole substitution will be the string (as substituted) up to the start of the substitution that raised the excep- |
tion. If a continue exception occurs during the evaluation of a command or variable substitution, an empty string will be substituted for |
that entire command or variable substitution (as long as it is well-formed Tcl.) If a return exception occurs, or any other return code is |
returned during command or variable substitution, then the returned value is substituted for that substitution. See the EXAMPLES below. |
In this way, all exceptional return codes are ``caught'' by subst. The subst command itself will either return an error, or will complete |
successfully.
EXAMPLES
When it performs its substitutions, subst does not give any special treatment to double quotes or curly braces (except within command sub-
stitutions) so the script
set a 44
subst {xyz {$a}}
returns ``xyz {44}'', not ``xyz {$a}'' and the script |
set a "p} q {r" |
subst {xyz {$a}} |
return ``xyz {p} q {r}'', not ``xyz {p} q {r}''. |
When command substitution is performed, it includes any variable substitution necessary to evaluate the script. |
set a 44 |
subst -novariables {$a [format $a]} |
returns ``$a 44'', not ``$a $a''. Similarly, when variable substitution is performed, it includes any command substitution necessary to |
retrieve the value of the variable. |
proc b {} {return c} |
array set a {c c [b] tricky} |
subst -nocommands {[b] $a([b])} |
returns ``[b] c'', not ``[b] tricky''. |
The continue and break exceptions allow command substitutions to prevent substitution of the rest of the command substitution and the rest |
of string respectively, giving script authors more options when processing text using subst. For example, the script |
subst {abc,[break],def} |
returns ``abc,'', not ``abc,,def'' and the script |
subst {abc,[continue;expr 1+2],def} |
returns ``abc,,def'', not ``abc,3,def''. |
Other exceptional return codes substitute the returned value |
subst {abc,[return foo;expr 1+2],def} |
returns ``abc,foo,def'', not ``abc,3,def'' and |
subst {abc,[return -code 10 foo;expr 1+2],def} |
also returns ``abc,foo,def'', not ``abc,3,def''.
SEE ALSO
Tcl(n), eval(n), break(n), continue(n)
KEYWORDS
backslash substitution, command substitution, variable substitution
Tcl 7.4 subst(n)