decode base64: invalid input

Question

Trying to decode base64 file on GNU/Linux, I get "base64: invalid input".

$ base64 test.zip | base64 -d > test2.zip
base64: invalid input
$ ll test*
-rw-r--r-- 1 user grp 152 19 11:41 test.zip
-rw-r--r-- 1 user grp  57 19 11:42 test2.zip

I tried dos2unix command, but it did not help.

My base64 version:

$ base64 --version
base64 (GNU coreutils) 5.97
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software.  You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.

Written by Simon Josefsson.

On my system at least, it's `-D` to decode, not `-d`. What does `base64 --help` say on your system? — John Zwinck, Mar 19 '13 at 02:58
Consider upgrading; the current version is at least 8.20 (from 2012) and probably more recent still. — Jonathan Leffler, Mar 19 '13 at 03:03
That version is what CentOS 5.x installs, so depending on who controls the environment he may not have the option. — Joe, Mar 19 '13 at 04:07
Yes, it's an old version linux. Red Hat Enterprise Linux Server release 5.3 (Tikanga) released at 2009/1/20 — andyf, Mar 19 '13 at 05:38

score 110 · Accepted Answer · edited Feb 28 '17 at 02:00

110

That version will not decode (by default) lines with separators, yet the encoder does that by default. (Newer versions don't have this problem.)

One solution:

base64 -w 0 foo.zip | base64 -d > foo2.zip

Alternate:

base64 foo.zip | base64 -di > foo2.zip

The -i option stands for (from the man page):

-i, --ignore-garbage
       When decoding, ignore non-alphabet characters.
[...]
Decoding require compliant input by default, use --ignore-garbage to
attempt to recover from non-alphabet characters (such as newlines)

edited Feb 28 '17 at 02:00

Felix

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answered Mar 19 '13 at 03:00

Joe

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FWIW only the alternate solution worked for me. Even with no line breaks, `base64 -d` was still complaining. – cdhowie May 10 '18 at 20:53
I put -i and didn't work. I put --ignore-garbage and it work :D – Quim Serra Jun 23 '20 at 12:25

score 6 · Answer 2 · answered Dec 19 '19 at 23:36

6

Or even more simply

base64 -di foo.zip > foo2.zip

answered Dec 19 '19 at 23:36

Shawn Lillemo

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Thanks Shawn, and welcome to StackOverflow. Your answer is nice and concise! To enhance it, you might consider explaining the `-di` options in a few words. – Jeremy Dec 20 '19 at 02:19

score 4 · Answer 3 · answered Jun 10 '20 at 23:32

4

If you're doing this on a mac, your version of base64 might not have the flexibility to handle ignoring garbage. If you brew install coreutils, you'll have the gbase64 utility and use it as Joe has described.

answered Jun 10 '20 at 23:32

Micah Elliott

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score 1 · Answer 4 · answered Jun 04 '20 at 22:16

1

You can also try using

echo -n

to suppress new lines and padding the input length to a multiple of 4 with one to three equal characters

answered Jun 04 '20 at 22:16

Tim Milstead

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decode base64: invalid input

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