I want to write a wrapper script that will read each file a line at a time, execute that line and store the PID for each line so that after a certain amount of time the processes can be killed.
I haven't implemented a full script for this but what I have written is here:
Code:
#!/bin/sh
while read line
do
$line
# command_to_run_simulator -simulator_arguments > log_file 2>&1 &
echo $!
done < $1
I was expecting that each line in the file would be read output and run. If I insert the commented line, an exact copy from the original file, it works fine. If I leave the variable in there then I get the following error:
Unexpected option '>'
It seems that when $line is expanded somehow the meaning of the redirection symbol is lost. Can anyone explain how $line is expanded and why the redirection is lost? As a secondary thing, is there a better way to achieve what I'm trying to do?
Please ask if anything isn't clear or I've missed relevant information. On that note, my shell is GNU bash, version 3.00.15(1)-release (x86_64-redhat-linux-gnu).
I'm trying to write a simple script program (C shell). I have a problem redirecting input into a variable. Say I have a variable called J, and there is file called result which contains just some number, say 5. Which command should I use to assign J value 5 from the file result. I tried the... (2 Replies)
how make assign the output of the command (for example: grep "file" "string" ) in a variable ($name)?
i thing how put the result of the command (grep , cut, find ecc) in a variable..
IT's Possible ?? (1 Reply)
how do you redirect stdout into a variable. whenever I try I get an ambiguous redirect error :( I am trying to validate some user input and failing miserably.
cal $MONTH $YEAR | grep -c "$DAY"
if the above is 1 then it is valid if 0 then not valid. I have been trying to redirect the output... (2 Replies)
for the below
grep -i $1 "${logdir}"* | grep -i adding | grep -iv equation | tail -1 | cut -d ':' -f 1
the result of the grep i want to redirect into some variable, i tried to do
veri=grep -i $1 "${logdir}"* | grep -i adding | grep -iv equation | tail -1 | cut -d ':' -f 1
but it is... (2 Replies)
hello
just i saw a really strange for cat
i have file (file1) contains line /home/rajiv/proj1/*.txt
now applied a commonds
DDPATH="$(cat file1)"
echo $DDPATH
it shows all the txt files in that folder like /home/rajiv/proj1/read1.txt /home/rajiv/proj1/read2.txt... (7 Replies)
Hi!
Been working on a script and I've been having a problem. I've finally narrowed it down to this variable I'm setting:
servername=$(awk -v FS=\/ '{ print $7 } blah.txt | sed 's\/./-/g' | awk -v FS=\- '{print $1}')"
This will essentially pare down a line like this:
... (7 Replies)
Hi, I read in this forum that for "https://www.unix.com/shell-programming-scripting/156008-integer-expression-expected-regular-expression.html
thanks! (7 Replies)
I've tried numerous commands, but I am not sure how to use sed in a loop. This is what I have:
VARZ contains CARD_FILE_LIST and it also contains CARD_FILE_LIST2
so
echo "$VARZ"
CARD_FILE_LIST
CARD_FILE_LIST2
I have a file with 60 lines in /tmp/testfile it and I want those lines deleted... (3 Replies)
Hello,
I am trying to print out the first string matching query with grep and I need your help.
My scenario:
Database
John F
4433 Street No 88 CA
Elisabeth Taylor
7733 Street No 26 ON
Jack Nicholson
0133 Green Park No 34 AR
John F 2
9399 Southpark No 02D UT
test.sh... (6 Replies)
I have a little code block (executing on AIX 7.1) that I cannot understand why the NOTFREE=0 does not appear to be assigned even though it goes through that block. This causes a unary operator issue.
#!/bin/bash
PLATFORM="AIX"
NEEDSPC=3000
set -x
if ; then
lsvg | grep -v rootvg | while... (6 Replies)
Discussion started by: port43
6 Replies
LEARN ABOUT CENTOS
tcl_detachpids
Tcl_DetachPids(3) Tcl Library Procedures Tcl_DetachPids(3)__________________________________________________________________________________________________________________________________________________NAME
Tcl_DetachPids, Tcl_ReapDetachedProcs, Tcl_WaitPid - manage child processes in background
SYNOPSIS
#include <tcl.h>
Tcl_DetachPids(numPids, pidPtr)
Tcl_ReapDetachedProcs()
Tcl_Pid
Tcl_WaitPid(pid, statusPtr, options)
ARGUMENTS
int numPids (in) Number of process ids contained in the array pointed to by pidPtr.
int *pidPtr (in) Address of array containing numPids process ids.
Tcl_Pid pid (in) The id of the process (pipe) to wait for.
int *statusPtr (out) The result of waiting on a process (pipe). Either 0 or ECHILD.
int options (in) The options controlling the wait. WNOHANG specifies not to wait when checking the process.
_________________________________________________________________DESCRIPTION
Tcl_DetachPids and Tcl_ReapDetachedProcs provide a mechanism for managing subprocesses that are running in background. These procedures
are needed because the parent of a process must eventually invoke the waitpid kernel call (or one of a few other similar kernel calls) to
wait for the child to exit. Until the parent waits for the child, the child's state cannot be completely reclaimed by the system. If a
parent continually creates children and doesn't wait on them, the system's process table will eventually overflow, even if all the children
have exited.
Tcl_DetachPids may be called to ask Tcl to take responsibility for one or more processes whose process ids are contained in the pidPtr
array passed as argument. The caller presumably has started these processes running in background and does not want to have to deal with
them again.
Tcl_ReapDetachedProcs invokes the waitpid kernel call on each of the background processes so that its state can be cleaned up if it has
exited. If the process has not exited yet, Tcl_ReapDetachedProcs does not wait for it to exit; it will check again the next time it is
invoked. Tcl automatically calls Tcl_ReapDetachedProcs each time the exec command is executed, so in most cases it is not necessary for
any code outside of Tcl to invoke Tcl_ReapDetachedProcs. However, if you call Tcl_DetachPids in situations where the exec command may
never get executed, you may wish to call Tcl_ReapDetachedProcs from time to time so that background processes can be cleaned up.
Tcl_WaitPid is a thin wrapper around the facilities provided by the operating system to wait on the end of a spawned process and to check a
whether spawned process is still running. It is used by Tcl_ReapDetachedProcs and the channel system to portably access the operating sys-
tem.
KEYWORDS
background, child, detach, process, wait
TclTcl_DetachPids(3)
11-03-2009
Redirect contained in variable not expanded as expected
. If I leave the variable in there then I get the following error
: