Question

I have the following simple script. However, it incorrectly gives the counter result to be 0.

#!/usr/local/bin/bash
f_name="test.stat"
S_Date="2012-02-10"
E_Date="2012-02-13"

awk 'BEGIN {FS="\t";s_time = mktime($S_Date);e_time = mktime($E_Date);counter=0}
     {if ($1 >= s_time && $1 <= e_time) counter++}
     END{print counter}' $f_name

The data file has the format: $Date $val

Answer 1

The awk command is in single quotes so $S_DATE and $E_DATE are being taken literally. You have a few options:

#!/usr/local/bin/bash
f_name="test.stat" S_Date="2012-02-10" E_Date="2012-02-13"

awk 'BEGIN {FS="\t";s_time = mktime('"$S_Date"');e_time = mktime('"$E_Date"');counter=0} {if($1 >= s_time && $1 <= e_time) counter++} END{print counter}' "$f_name"

#!/usr/local/bin/bash
f_name="test.stat" S_Date="2012-02-10" E_Date="2012-02-13"

awk "BEGIN {FS=\"\\t\";s_time = mktime($S_Date);e_time = mktime($E_Date);counter=0} {if(\$1 >= s_time && \$1 <= e_time) counter++} END{print counter}" "$f_name"

Or, my favorite:

#!/usr/local/bin/bash
f_name="test.stat" S_Date="2012-02-10" E_Date="2012-02-13"

awk "$f_name" <<EOF
BEGIN {
    FS="\t"
    s_time = mktime($S_Date)
    e_time = mktime($E_Date)
    counter=0
} 
{ if(\$1 >= s_time && \$1 <= e_time) counter++ } 
END{print counter}
EOF