Converting bash script to zsh for converting bytes to 'readable'

[TJ Luoma <luomat@gmail.com>]

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Several years ago I came across this script (below) as a 'bash' script. I
believe the comments came from the original as well:


BYTES="$@"

#MBYTES='1024'
MBYTES='1000'

# Array of suffixes
declare -a METRIC=(' Bytes' 'KB' 'MB' 'GB' 'TB' 'XB' 'PB')

# magnitude of 2^10
MAGNITUDE=0

# change this numeric value to increase decimal precision
PRECISION="scale=1"

# numeric arg val (in bytes) to be converted
UNITS=$(echo "$BYTES" | tr -dc '[0-9]')

# compares integers (b/c no floats in bash)
while [ ${UNITS/.*} -ge ${MBYTES} ]
do
# floating point math via `bc`
UNITS=`echo "$PRECISION; $UNITS/${MBYTES}" | bc`

# increments counter for array pointer
((MAGNITUDE++))
done

echo "$BYTES bytes"

echo "$UNITS ${METRIC[$MAGNITUDE]}"

I don't really understand what the 'while' loop is doing, and I don't know
if zsh has 'floats' (which I assume is 'floating point'?).

So, given my limited knowledge here, I tried to implement the same thing in
zsh, and this is what I came up with:

BYTES="$@"

#MBYTES='1024'
MBYTES='1000'

PRECISION="scale=2"

if [ "$MBYTES" = "1000" ]
then
METRIC=('KB' 'MB' 'GB' 'TB' 'XB' 'PB')
else
METRIC=('KiB' 'MiB' 'GiB' 'TiB' 'XiB' 'PiB')
fi

for BYTES in "$@"
do

MAGNITUDE=0

UNITS=$(echo "$BYTES" | tr -dc '[0-9]')

if [[ "$UNITS" != "" ]]
then

while [ ${UNITS/.*} -ge $MBYTES ]
do
UNITS=$(echo "$PRECISION; $UNITS/$MBYTES" | bc)

((MAGNITUDE++))

done

echo "$UNITS ${METRIC[$MAGNITUDE]}"

fi

done


Does that look correct to you? Did I miss anything? It appears to work in
my (limited, so far) testing, but I'm worried that I'm overlooking
something.

Alternatively: is there another / easier way of doing this that I should
use instead? Some 'zmodload' or something?

Thanks for any pointers.

Tj



--
TJ Luoma
TJ @ MacStories
Personal Website: luo.ma (aka RhymesWithDiploma.com)
Twitter: @tjluoma