Sponsored Content
Top Forums Shell Programming and Scripting [BASH] Script to manage background scripts (running, finished, exit code) Post 302921390 by Corona688 on Thursday 16th of October 2014 04:45:05 PM
Old 10-16-2014
I don't think "unset" really does what you think it does -- deleting from the middle of an array like that. Whenever I do that I end up with "holes", indexes that still exist but have no value. Associative arrays in shell is pretty chancy anyhow, you often won't have a bash new enough, or have bash at all.

Why keep an array of arguments when you already have one, $@

A construct I often use:

Code:
#!/bin/bash

# This is a ring buffer.  Append at PIDS[$PW], read at PIDS[$PR].
# PW increments when a process is added, PR when a process dies,
# and both wrap at MAX.  Order is not important when removing
# since it shuffles the last process to whatever got deleted.
PIDS=()
PW=0
PR=0
MAX=2

running() {     # running "arrayindex"
        ps "${PIDS[$1]}" >/dev/null
}

add() {         # add "pid"
        PIDS[$PW]="$1"
        PW=$(( (PW+1)%MAX ))
        ((TOTAL++))
}

rem() {         # rem "arrayindex"
        # Take PID from the end, plunk it where the one to be deleted is
        PW=$(( (PW-1) % MAX ))
        [[ "$PW" -lt 0 ]] && PW=$((PW+MAX))

        PIDS[$PR]="${PIDS[$PW]}"
        ((TOTAL--))
}

# Start each given program in turn
for X in "$@"
do
        while [[ "$TOTAL" -ge "$MAX" ]]
        do
        for((N=0, I=PR; (TOTAL>=MAX) && (N<TOTAL); N++, I=(I+1)%MAX ))
        do
                if ! running "$I"
                then
                        rem "$I"
                        break
                fi
        done
                [[ "$TOTAL" -ge "$MAX" ]] && sleep 0.1
        done

        # Refers to array indexes, i.e. /tmp/$$-0 for array index 0.
        $X >/tmp/$$-$PW &
        add "$!"
done

while [[ "$TOTAL" -ge "$MAX" ]]
do
        for((N=0, I=PR; N<$TOTAL; N++, I=(I+1)%MAX ))
        do
                if ! running "$I"
                then
                        rem "$I"
                        break
                fi
        done
done

wait
rm -f /tmp/$$-*


Last edited by Corona688; 10-16-2014 at 05:54 PM..
This User Gave Thanks to Corona688 For This Post:
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

exit status of Invoking two or more scripts in background

I have a sript which is going to trigger other 3 scripts in background simultaneously for eg: Main Script:(main.sh) ----------- sh a.sh & sh b.sh & sh c.sh & How to catch the exit status and store it in a variable for all those three scripts in main script. Is there any other way of... (4 Replies)
Discussion started by: Omkumar
4 Replies

2. UNIX for Dummies Questions & Answers

background job finished notification

In my last job someone gave me the command to put in my .profile that let me know when a job I had running in the background finished. It was a word about 5 char long. I can't remember it! (4 Replies)
Discussion started by: nkeller
4 Replies

3. Shell Programming and Scripting

Issues with exit after running jobs in background

I have the following sample script to run a script the jobs with the same priority(in this case field3) in parallel; wait for the jobs to finish and run the next set of jobs in parallel.When all the lines are read exit the script. I have the following script which is doing evrything I want... (1 Reply)
Discussion started by: hyennah
1 Replies

4. Shell Programming and Scripting

Capturing the exit status of the script running in background

Hi All, I have a scenario where I am executing some child shell scripts in background (using &)through a master parent script. Is there a way I can capture the exit status of each individual child script after the execution is completed. (2 Replies)
Discussion started by: paragkalra
2 Replies

5. Shell Programming and Scripting

Catch exit code of specific background process

Hi all, i hava a specific backgroud process. I have de PID of this process. At some time, the process finish his job, is there any way to catch the exit code? I use "echo $?" normally for commands. Thanks! (2 Replies)
Discussion started by: Xedrox
2 Replies

6. Shell Programming and Scripting

Bash Question: HowTo Exit Script with User Input While Process is Running Mid-Loop?

Hi, I have written a script that allows me to repetitively play a music file $N times, which is specified through user input. However, if I want to exit the script before it has finished looping $N times, if I use CTRL+c, I have to CTRL+c however many times are left in order to complete the loop.... (9 Replies)
Discussion started by: hilltop_yodeler
9 Replies

7. Shell Programming and Scripting

Running scripts in background

Hi, below is my master script wihch inturn runs 2 scripts in background #master_script.sh ./subscript1.sh & ./subscript2.sh & executed the master_script.sh from unix command prompt $ ./master_script.sh it is executing the subscripts and they are completing fine, however master_script.sh is... (2 Replies)
Discussion started by: JSKOBS
2 Replies

8. Shell Programming and Scripting

Problems running scripts in the background

Hi Could someone offer some help on this problem I've got with running a background process. As part of a script that does a stop/start/status for a piece of software called SAS, the following extract is from part of the start step. My issue is that when the script is run, the control... (0 Replies)
Discussion started by: GavP
0 Replies

9. Shell Programming and Scripting

Terminal running bash/rsync script does not close with exit (MacOS High SIerra)

Hello, I am running a bash script to do an rsync back on a computer running MacOS High Sierra. This is the script I am using, #!/bin/bash # main backup location, trailing slash included backup_loc="/Volumes/Archive_Volume/00_macos_backup/" # generic backup function function backup {... (12 Replies)
Discussion started by: LMHmedchem
12 Replies
TOTAL(1)						      General Commands Manual							  TOTAL(1)

NAME
total - sum up columns SYNOPSIS
total [ -m ][ -sE | -p | -u | -l ][ -i{f|d}[N] ][ -o{f|d} ][ -tC ][ -N [ -r ]] [ file .. ] DESCRIPTION
Total sums up columns of real numbers from one or more files and prints out the result on its standard output. By default, total computes the straigt sum of each input column, but multiplication can be specified instead with the -p option. Likewise, the -u option means find the upper limit (maximum), and -l means find the lower limit (minimum). Sums of powers can be computed by giving an exponent with the -s option. (Note that there is no space between the -s and the exponent.) This exponent can be any real number, positive or negative. The absolute value of the input is always taken before the power is computed in order to avoid complex results. Thus, -s1 will produce a sum of absolute values. The default power (zero) is interpreted as a straight sum without taking absolute values. The -m option can be used to compute the mean rather than the total. For sums, the arithmetic mean is computed. For products, the geomet- ric mean is computed. (A logarithmic sum of absolute values is used to avoid overflow, and zero values are silently ignored.) If the input data is binary, the -id or -if option may be given for 64-bit double or 32-bit float values, respectively. Either option may be followed immediately by an optional count, which defaults to 1, indicating the number of double or float binary values to read per record on the input file. (There can be no space between the option and this count.) Similarly, the -od and -of options specify binary double or float output, respectively. These options do not need a count, as this will be determined by the number of input channels. A count can be given as the number of lines to read before computing a result. Normally, total reads each file to its end before producing its result, but this behavior may be overridden by inserting blank lines in the input. For each blank input line, total produces a result as if the end-of-file had been reached. If two blank lines immediately follow each other, total closes the file and proceeds to the next one (after reporting the result). The -N option (where N is a decimal integer) tells total to produce a result and reset the calculation after every N input lines. In addition, the -r option can be specified to override reinitialization and thus give a running total every N lines (or every blank line). If the end of file is reached, the current total is printed and the calculation is reset before the next file (with or without the -r option). The -tC option can be used to specify the input and output tab character. The default tab character is TAB. If no files are given, the standard input is read. EXAMPLE
To compute the RMS value of colon-separated columns in a file: total -t: -m -s2 input To produce a running product of values from a file: total -p -1 -r input BUGS
If the input files have varying numbers of columns, mean values will certainly be off. Total will ignore missing column entries if the tab separator is a non-white character, but cannot tell where a missing column should have been if the tab character is white. AUTHOR
Greg Ward SEE ALSO
cnt(1), neaten(1), rcalc(1), rlam(1), tabfunc(1) RADIANCE
2/3/95 TOTAL(1)
All times are GMT -4. The time now is 03:56 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy