Question

“awk” can be used to process simple tables. Given a table below:

npu29:yinglir>cat table.txt

1 2 3
2 3 4
5 6 7
3 6 9
2 3 4
3 4 1

The simple command below can be used to filter the table:

npu29:yinglir>cat table.txt | awk ' { if (($3 >= 3) && ($3 <= 4)) print $0 } '

1 2 3
2 3 4
2 3 4

You can also write a simple c-shell script as below. The c-shell script will take the arguments and pass the min and max to awk. See below on how it works:

npu29:yinglir>use_awk.csh

Usage: use_awk.csh file_name min max

npu29:yinglir>use_awk.csh table.txt 3 4

print out lines with column 3 between 3 and 4

1 2 3
2 3 4
2 3 4

npu29:yinglir>use_awk.csh table.txt 4 7

print out lines with column 3 between 4 and 7

2 3 4
5 6 7
2 3 4

              npu29:yinglir>

What to turn in:

1.      Your script
2.      Sample run log on a different table you created.

Answer 1

SCRIPT:

#! /bin/csh -f

if ($#argv != 3) then
echo "Usage: use_awk.csh file_name min max"
exit 0
endif

set file_name=$1
set min=$2
set max=$3

echo "print out lines with column 3 between $min and $max"
cat $file_name | awk ' { if (($3 >= '$min') && ($3 <= '$max')) print $0 } '

OUTPUT :

% ./use_awk.csh
Usage: use_awk.csh file_name min max

% ./use_awk.csh table.txt 3 4
print out lines with column 3 between 3 and 4
1 2 3
2 3 4
2 3 4

% ./use_awk.csh table.txt 1 2
print out lines with column 3 between 1 and 2
3 4 1

% ./use_awk.csh table.txt -1 0
print out lines with column 3 between -1 and 0

SCREENSHOT :

#1 /bin/csh -f if ($#argv !- ) then echo "Usage: use_awk.csh file_name min max" exit θ endif set file_name $1 set min $2 set max $3 echo "print out lines with column 3 between $min and $max" cat $file_name | awk '1 if (($3$min') && ($3$max")) print $0'