Running perl command form shell script

Question

I have a list of points coordinates in 2 column format first column x-axis, second column y-axis, and I'd like to make a script to rescale the axis.

input file example
4 3
3 6

output file example (rescale to 10 10)
10 5
7.5 10

To do that, I first get the biggest coordinate on both column (using sort, head and cut), and then I interpolate all lines using a perl substitute regexp.

So I scripted that :

#!/bin/sh
# run:  $ ./normalize x y input_file output_file
X=$1
Y=$2
INPUT=$3
OUTPUT=$4

BIGGEST_FIRST_COLUMN=$(sort -nrk1 $INPUT | head -n1 | cut -d ' ' -f 1)
BIGGEST_SECOND_COLUMN=$(sort -nrk2 $INPUT | head -n1 | cut -d ' ' -f 2)

PERL_CMD="'s!([\d.]+)\s([\d.]+)!(\$1/$BIGGEST_FIRST_COLUMN*$X).\" \".(\$2/$BIGGEST_SECOND_COLUMN*$Y)!e'"

CMD="perl -pe $PERL_CMD $INPUT > $OUTPUT"
echo "Run the following cmd : "
echo $CMD

$CMD

This code output the perl onliner I want to run and then try to run it. At this point, the perl oneliner is working : I can copy-paste it and running it by hand and it gives the correct output. Nevertheless, I got a bug when the script run it automatically :

Can't find string terminator "'" anywhere before EOF at -e line 1.

I suppose this is due to some problem in my comprehension of " and ' in shell, but at this point, I have no idea... So if you have any tips, welcome

alsjflalasjf.dev · Accepted Answer · 2016-03-05 14:30:59Z

1

You should change the last line:

#!/bin/sh
# run:  $ ./normalize x y input_file output_file
X=$1
Y=$2
INPUT=$3
OUTPUT=$4

BIGGEST_FIRST_COLUMN=$(sort -nrk1 $INPUT | head -n1 | cut -d ' ' -f 1)
BIGGEST_SECOND_COLUMN=$(sort -nrk2 $INPUT | head -n1 | cut -d ' ' -f 2)

PERL_CMD="'s!([\d.]+)\s([\d.]+)!(\$1/$BIGGEST_FIRST_COLUMN*$X).\" \".(\$2/$BIGGEST_SECOND_COLUMN*$Y)!e'"

CMD="perl -pe $PERL_CMD $INPUT > $OUTPUT"
echo "Run the following cmd : "
echo $CMD

# $CMD  < no
eval $CMD

answered Mar 5, 2016 at 14:30

alsjflalasjf.dev

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Comments

Borodin · Accepted Answer · 2016-03-06 04:12:36Z

0

Here's a Perl one-liner that will do as you ask without needing the shell to preprocess the data

perl -MList::Util=max -E'@d=map[split],<>;for $i(0,1){$m=max map $$_[$i],@d; $$_[$i]*=10/$m for @d} say qq{@$_} for @d' data.txt

output

10 5
7.5 10

answered Mar 6, 2016 at 4:12

Borodin

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1 Comment

Bromind Over a year ago

Ahah, nice ! Not comfortable enough to write one-liner like that yet :-)

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