Only get hash value using md5sum (without filename)

Question

I use md5sum to generate a hash value for a file. But i only need to receive the hash value, not the file name.

md5=`md5sum ${my_iso_file}`
echo ${md5}

3abb17b66815bc7946cefe727737d295 ./iso/somefile.iso

How can i 'strip' the file name and only remain the value ?

Answer 1

You can use cut to split the line on spaces and return only the first such field:

md5 = $(md5sum ${my_iso_file} | cut -d ' ' -f 1)

Answer 2

md5=`md5sum ${my_iso_file} | cut -b-32`

Answer 3

md5="$(md5sum "${my_iso_file}")"
md5="${md5%% *}" # remove the first space and everything after it
echo "${md5}"

Answer 4

Another way:

md5=$(md5sum ${my_iso_file} | sed '/ .*//' )

Answer 5

Well another way :)

md5=`md5sum ${my_iso_file} | awk '{ print $1 }'`

Answer 6

md5=$(md5sum < index.html | head -c -4)

Answer 7

One way:

set -- $(md5sum $file)
md5=$1

Another way:

md5=$(md5sum $file | while read sum file; do echo $sum; done)

Another way:

md5=$(set -- $(md5sum $file); echo $1)

(Do not try that with back-ticks unless you're very brave and very good with backslashes.)

The advantage of these solutions over other solutions is that they only invoke md5sum and the shell, rather than other programs such as awk or sed. Whether that actually matters is then a separate question; you'd probably be hard pressed to notice the difference.

Answer 8

Thx all, for the examples. As always, there are many ways to skin a cat :-))

Answer 9

md5sum $file | read SUM IGNORE

(read is a builtin, which will be faster than executing an external binary like awk or sed)

Answer 10

On Mac OS X:

md5 -q file

Answer 11

md5=$(md5sum < $file | tr -d ' -')