stuck

magnia · 06-09-2007 01:52AM #1

#!/bin/bash
echo $1 | cat - $2 >> /tmp/$$ && mv /tmp/$$ $2

im trying to get the first argument to go in the middle of the second argument which is a file, anyone any ideas.i have only managed to get it to go on the end or the front.

been fiddling about with wc -l, i get the number of lines but not sure how i use that to insert the argument

Snowbat · 06-09-2007 07:20AM

I'm curious why you'd want to add something in the middle of a file but...

#!/bin/bash
HALFWAY=$((`cat $2 | wc -l`/2))
awk "NR <= $HALFWAY" $2 > /tmp/$$
echo $1 >> /tmp/$$
awk "NR > $HALFWAY" $2 >> /tmp/$$
mv /tmp/$$ $2

magnia · 06-09-2007 08:55PM

cant use awk or seds but what u wrote looks good. trying to learn unix out of a book. this was just one of the questions at the end of a chapter. can it be done with awk or sed.

Snowbat · 06-09-2007 11:24PM

Even my router has awk and sed available but you could do it this way:

#!/bin/bash
HALFWAY=$((`cat $2 | wc -l`/2))
COUNTER=0
for i in `cat $2`;
do
        echo $i >> /tmp/$$
        if [ $COUNTER -eq $HALFWAY ]
        then
                echo $1 >> /tmp/$$
        fi
        let COUNTER+=1
done
mv /tmp/$$ $2

Khannie · 07-09-2007 09:44AM

tail has an option to specify number of lines. Off the top of my head, it's what I'd use.

stuck

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