I am writing a shell script. I have a file that looks like this.
#some comments
22 ssh
25 smpt
80 http
And I want to iterate over the lines putting the first column into
var1 and the second column into var2.
I thought this would work:
#!/bin/sh
export INFILE=/etc/iptables/tcp.accept.dest.ports
if [ -f $INFILE ]; then
#get the lines, ignoring empties and comments
lines=`cat $INFILE | grep -v "^[[:space:]]*#" | grep -v '^[[:space:]]*$'
2>/dev/null`
for line in $lines; do
col1=`echo $line | awk '{print $1}'`
col2=`echo $line | awk '{print $2}'`
echo "column 1 is $col1 and column 2 is $col2"
done
else
echo "Can't find $INFILE"
fi
But it doesn't behave as expected.
I know I could do it easily in perl or python, but I am trying to
limit myself to the bare bones UNIX utilities here.
Ideally the script could handle the case where var2 is empty,
something like
if (not empty var2)
do something
else
do the default this
fi
Suggestions?
John
