Removing duplicate items from an array Post: 303007390

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Top Forums Shell Programming and Scripting Removing duplicate items from an array Post 303007390 by Don Cragun on Thursday 16th of November 2017 04:32:31 AM

11-16-2017

Registered User

I don't think your code works as well as you think it does. Try running your script again telling it that you want it to process 5 numbers and then enter the same number 5 times. Do you get the results you wanted? Then try running your script again telling it that you want it to process 5 numbers and then enter 1, 2, 1, 3, and 1. Would you expect the final result to be 2 3 1 or 1 2 3?

See if this works better for you:

Code:

#!/bin/bash
echo "This is a sample Prog to remove duplicate integer items from an array"
echo "How many numbers do you want to insert"
read n
for (( i=0; i<$n; i++ ))
do
	echo "Enter Number"
	read num
	arr[i]=$num
done
echo "Insertion is done, Below are the elements of the array"
echo ${arr[@]}

for (( i=0; i<$((n-1)); i++ ))
do
	echo "------------arr[i] here is ${arr[i]}-------" 
	for (( j=$((i+1)); j<$n; j++ ))
	do
		echo "arr[j] here is ${arr[j]}"
		if [[ arr[i] -eq arr[j] ]]
		then
			echo "There is a duplicate!!"
			arr=(${arr[@]:0:$j} ${arr[@]:$((j+1))})
			((j--))
			((n--))
		fi
	done
done
echo ${arr[@]}

This seems to work OK with both bash version 3.2.57(1)-release (x86_64-apple-darwin16) and with ksh version (AT&T Research) 93u+ 2012-08-01. I assume it will also work with more recent releases of both of these shells.

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peekfd

PEEKFD(1)							   User Commands							 PEEKFD(1)

NAME

       peekfd - peek at file descriptors of running processes

SYNOPSIS

       peekfd [-8,--eight-bit-clean] [-n,--no-headers] [-f,--follow] [-d,--duplicates-removed] [-V,--version] [-h,--help] pid [fd] [fd] ...

DESCRIPTION

       peekfd  attaches to a running process and intercepts all reads and writes to file descriptors.  You can specify the desired file descriptor
       numbers or dump all of them.

OPTIONS

       -8     Do no post-processing on the bytes being read or written.

       -n     Do not display headers indicating the source of the bytes dumped.

       -c     Also dump the requested file descriptor activity in any new child processes that are created.

       -d     Remove duplicate read/writes from the output.  If you're looking at a tty with echo, you might want this.

       -v     Display a version string.

       -h     Display a help message.

FILES

       /proc/*/fd
	      Not used but useful for the user to look at to get good file descriptor numbers.

ENVIRONMENT

       None.

DIAGNOSTICS

       The following diagnostics may be issued on stderr:

       Error attaching to pid ...
	      An unknown error occured while attempted to attach to a process.. you may need to be root.

BUGS

       Probably lots.  Don't be surprised if the process you are monitoring dies.

AUTHOR

       Trent Waddington <trent.waddington@gmail.com>

SEE ALSO

       ttysnoop(8)

Linux								    APRIL 2007								 PEEKFD(1)