Shell Programming and Scripting

GigabitEthernet0/0 is up, line protocol is up
     1 input errors, 0 CRC, 0 frame, 1 overrun, 0 ignored
     275 output errors, 0 collisions, 3 interface resets
GigabitEthernet0/1 is up, line protocol is up
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     42 output errors, 0 collisions, 3 interface resets

Interface, Input Errors, Output Errors
GigabitEthernet0/0, 1, 275
GigabitEthernet0/1, 0, 42

for line in $(cat $DATAFILE/$rname.intfs)
do
     intf=$(echo $line | grep "line protocol is " | awk '{print $1}')
     inerrs=$(echo $line | grep "input error" | sed 's/^[ \t]*//;s/[ \t]*$//' | awk '{print $1}')
     outerrs=$(echo $line | grep "output error" | sed 's/^[ \t]*//;s/[ \t]*$//' | awk '{print $1}')
     echo "$intf,$inerrs,$outerrs" >intf.csv
done

sed 's/ .*$/,/;N;s/ input.*$/,/;N;s/ output.*$//;s/\n//g' < $DATAFILE/$rname.intfs

GigabitEthernet0/0,     1,     275
GigabitEthernet0/1,     0,     42

while read line
do
   whatever
   echo "Here is my output"
done < $DATAFILE/$Rname.intfs > intf.csv

while read firstline
do
   read secondline
   read thirdline
   # Some processing here
   echo                                       # Whatever you have built
done < $DATAFILE.......  > intf.csv

while read intf junk
do
   read inerrs  junk
   read outerrs junk

   echo "$intf, $inerrs, $outerrs"
done < $DATAFILE/$rname.intfs > intf.csv

awk 'BEGIN {print "Interface, Input Errors, Output Errors"} {printf "%s%s", $1, !(NR%3)?RS:", "}' file
Interface, Input Errors, Output Errors
GigabitEthernet0/0, 1, 275
GigabitEthernet0/1, 0, 42