Using Nested loops in Unix

debumail186 · 11-13-2014, 07:12 PM

Hello Gurus,

Hope you are having a good day..

I am trying to built some code with nested loops in unix.

Here is some background...

I have a directory , wherein everyday 2 types of files are generated ..lets say by the name 'date'*3.log and 'date'*4.log

These files have a unique layout. The command is run once everyday to generate a file everyday. What I do is a compare between the file generated today and the one generated yesterday using diff..nd something like below

diff 1.log 2.log | tail -n +2 | head -n -4 |awk '{print $2,$3,$4,$5,$6}' > 3.log

to bring it to a specific format.. and further passing it to a perl script to format it further and finally doing a grep to remove unwanted entities.

Need your help with the piece of code which I been trying to make it to work. I am trying to build 2 loops with i and j variables to help generate the final log files in the required format.

Attaching the script as well. Pls advise.

Thanks
Dev

debumail186 · 11-14-2014, 12:04 PM

Hi guys,

Any advise in this regard is really appreciated.

Thanks
Dev

nbritton · 11-14-2014, 01:30 PM

Quote:

Originally Posted by debumail186

Hi guys,

Any advise in this regard is really appreciated.

Thanks
Dev

I need more information, like what does the input look like and what do you want the output to look like? Attach some examples of the log files you want to process.

A basic nested for loop is as follows:

Code:

for i in x
do
	for j in x
	do

	done
done

Here is an example:

Code:

#!/bin/bash
# box.sh

if [ $# -lt 2 ]; then
        echo "Error: you must specify two integer arguments."
        echo "Example: $0 x y"
        exit 1
fi

if ! [[ $1 =~ ^[0-9]+$ ]] ; then
        echo "Error: argument 1 is not a positive integer."
        exit 1
fi

if ! [[ $2 =~ ^[0-9]+$ ]] ; then
        echo "Error: argument 2 is not a positive integer."
        exit 1
fi

for x in $(seq $1)
do
        for y in $(seq $2)
        do
                printf .
        done
        echo
done