For loop in a awk command - shell

Question

I have a file which has rows , now i want to read it'w value from awk command in Unix. I am able to read that file , but i have added a for loop to traverse all the data into the file. But my for loop is not ending it is going in infinite loop.
Below code i am using to read the file and get the data of $1 ,$2 and $3 position
file=$1;
nbrClients=`wc -l $file | cut -d' ' -f1`;
echo $nbrClients;
awk '{
for(i=0; i<=$nbrClients; ++i)
{print $1 $2 $3}
}' $file
File which i am reading has below format :
abc 12 test.txt
abc 12 test.txt
abc 12 test.txt
abc 12 test.txt
abc 12 test.txt
abc 12 test.txt
So for this nbrClients value will be 6 and it should loop for 6 times but it is not doing so .Please suggest what wrong i am doing in this.
Here is the full code which i am trying to :
file=$1;
nbrClients=`wc -l $file | cut -d' ' -f1`;
echo $nbrClients;
file=$1;
cat | awk '{
fileName=$1
tnxCount=$2
for i in `seq 1 $tnxCount`
do
echo "Starting thread number $i"
nohup perl /home/user/abc.pl -i $fileName >>/home/user/test_load_${today}.out 2>&1 &
done
}' $file;

Answer 1

I think the problem here is that you're under the impression that the for loop is what will cause awk to step through your input file, whereas it's awk's nature to do that already.
Awk works by taking a set of condition { statement } pairs, and then FOR EACH LINE OF INPUT, evaluating the condition, and if it rings true, executing the statement. Note that conditions can be statements (since functions and other commands have a return value) and statements can include if constructs, so there's a lot of flexibility here.
Note that awk can also reduce or simplify stuff you'd do in a shell script. Consider the following:
#!/bin/sh
file="$1"
awk '
NR==FNR {
ClientCount++
next
}
FNR==1 {
printf "%s: %d\n", FILENAME, ClientCount
}
{
print $1, $2, $3
}
' "$file" "$file"
This script reads your input file twice -- once to count the lines (so that the line count can be placed at the top of theoutput), and once to process the lines, printing the first three fields. The script is composed of three condition { statement } groupings:
The first one is the counter. It only operates on the first instance of the file, and the next command insures that no other commands will be run on that file.
The second one operates on the first line of the file. But since the first condition captured all of the first file, this statement will only be executed once, when the first line of the second file is in play.
The third one is what prints the bulk of your output. With awk, when no condition is included, the condition is assumed to be "true", so this statement runs for each line of the second file.
The awk script could of course be compressed onto a single line, I've spaced it out for easier reading.
Note also that this method of keeping or showing a line count might be a little heavy handed. If you know that you're just showing a line count, you can use the internal awk variable NR. At the point in your script where the second condition is evaluated, NR-1 is the line count of the previous file, so you could use:
#!/bin/sh
file="$1"
awk '
NR==FNR {
next
}
FNR==1 {
printf "%s: %d\n", FILENAME, NR-1
}
{
print $1, $2, $3
}
' "$file" "$file"

Answer 2

updating the answer based on comment and latest version of the question
file=$1;
nbrClients=`wc -l $file | cut -d' ' -f1`;
echo $nbrClients;
file=$1;
cat $file | awk -v fileName="$1" -v tnxCount="$2" '{
system("echo "Starting thread number $i"")
system("nohup perl /home/user/abc.pl -i $fileName >>/home/user/test_load_${today}.out 2>&1 &")
}';