Is there a terminal command in Mac OS X which will base64 encode a file or stdin?

  • 7
    Be aware that although the base64-encoding syntax is consistent from one OS to another, the base64-decoding syntax is either base64 -d or base64 -D depending on your operating system. OSX uses -D. Nov 30, 2012 at 22:06
  • 1
    @ChrisJohnson If used in concert with openssl the flag for decoding is -d on OS X (10.10 Yosemite). Jun 10, 2015 at 12:11
  • Simply echo -n password | base64 in your MacOS Terminal; and echo -n password | base64 -D to decode.
    – Bugs Bunny
    May 30 at 19:29

19 Answers 19


openssl can do this for you, and it's all installed with OS X by default; no need to install darwinports.

$ openssl base64 -in <infile> -out <outfile>

Without the -in option reads from stdin

  • 110
    Use openssl base64 < path/to/file.png | tr -d '\n' | pbcopy or cat path/to/file.png | openssl base64 | tr -d '\n' | pbcopy to skip writing to a file and just copy the base64-encoded output to the clipboard without the line breaks. Apr 12, 2011 at 13:07
  • 6
    And use a -d flag to decode.
    – kenny
    Dec 11, 2013 at 22:26
  • 14
    In mac, To base64 encode a string: openssl base64 -e <<< ram and to decode: openssl base64 -d <<< cmFtCg==
    – Ram Patra
    Nov 13, 2014 at 10:52
  • 14
    @mathias if you want no newlines openssl base64 [-e] -A does that. + @kenny on decode if input does not have newline every 76 chars at most, including the no-newlines case I just stated, you need -d -A or you will get missing or corrupted data with no error message (although there is a pending bug report which may result in a fix to that). May 27, 2015 at 14:54
  • 2
    @Ram, openssl base64 -e <<< ram actually encodes 4 bytes, including a trailing line feed; see hexdump <<< ram.
    – Arjan
    Jun 3, 2015 at 20:39

Openssl can be used more succinctly:

echo -n 'input' | openssl base64

[ echo -n -> must be used, or encoding will be done including new line character ]


openssl base64 <ENTER> [type input] <CTRL+D>
  • 18
    The "echo" solution adds a LF (line feed) char to the end of the input string, though. Better use: echo -n 'input' Jul 17, 2012 at 15:17
  • 14
    And even a bit more succinct openssl base64 <<< input Jun 6, 2013 at 16:57
  • 5
    Or just use base64 without openssl. Either way, I need to press Ctrl+D twice. And beware, @Garret: in Bash, with or without openssl, openssl base64 <<< superuser and openssl base64 <<< "superuser" erroneously yield c3VwZXJ1c2VyCg==, as the "here string" then still includes a line feed! (Apparently not only in Bash, but also in zsh, ksh and yash. See hexdump <<< superuser. The Base64 result should be c3VwZXJ1c2Vy.)
    – Arjan
    Jun 3, 2015 at 20:37
  • @Arjan I'd hesitate to use the word "erroneously" - as you pointed out, the here-string includes a line feed, but for good reason - unix.stackexchange.com/questions/20157/… . echo -n is preferred if you don't need the newline. It's certainly something to be aware of. Jun 5, 2015 at 7:33
  • 3
    You could use printf in place of echo -n
    – Jason S
    Sep 5, 2016 at 6:08

Try using:

base64 -i <in-file> -o <outfile>

It should be available by default on OS X.

  • 2
    Add --decode to reverse the process from base64 to normal. Nov 2, 2018 at 14:05
  • 3
    This is better for encoding for SVG because it creates one line. This is cleaner than the output from openssl base64. Thanks!
    – Shanimal
    Apr 18, 2019 at 1:35
  • I didn't want to use files so you can do echo -n "something" | base64 Feb 3, 2022 at 22:51

On macOS I always use:

echo -n "STRING" | base64

-n is to avoid a new line character on the end of the line.

  • This also works on Windows if you're running Cmder. May 27, 2020 at 2:03
  • This works for me in mac Apr 5, 2021 at 11:52

base64 command is available by default on my OS X 10.9.4.

You can use base64 <<< string and base64 -D <<< string to encode and decode a string in the terminal, or base64 -in file and base64 -D -in file to encode and decode a file.

  • Do you have an example? I get Invalid characer in input stream when using <<<...I have tried with ", ' and nothing around the string.
    – Jonas
    Sep 20, 2016 at 11:46
  • @Jonas What shell are you in? You can use this in bash and zsh.
    – WKPlus
    Sep 21, 2016 at 12:42
  • Ah, nevermind, it works!
    – Jonas
    Sep 22, 2016 at 8:46
  • 7
    Please note base64 <<< cat is equivalent to echo cat|base64, not echo -n cat|base64. Basically the automatic linefeed will be added to the base64 encoded string, and that might not be what you want.
    – Bill
    Apr 12, 2020 at 3:29

Since Python is provided with OS X by default, you can use it as below:

$ echo FOO | python -m base64
$ echo Rk9PCg== | python -m base64 -d

Or install coreutils via Brew (brew install coreutils) which will provide base64 command:

$ echo FOO | base64
$ echo Rk9PCg== | base64 -d

You can also pipe it right to the clipboard (at least on mac):

openssl base64 -in [filename] | pbcopy

  • 1
    golfing: base64 < [filename] | pbcopy
    – totels
    Aug 11, 2016 at 19:57
  • Nice idea! xclip -sel clip would be the equivalent to pbcopy in X11.
    – Besworks
    May 20, 2022 at 0:01


Python comes preinstalled on all macs nowadays.

In Terminal run python (or ipython).

Encode a file:

 base64data = open('myfile.jpg','rb').read().encode('base64')

Decode a file:

data = open('myfile.txt').read().decode('base64')

Of course, both operations can be converted to a oneliner but this way it is more readable.


## encode to base64 (on OSX use `-output`)
openssl base64 -in myfile.jpg -output myfile.jpg.b64

## encode to base64 (on Linux use `-out`)
openssl base64 -in myfile.jpg -out myfile.jpg.b64

## decode from base64 (on OSX `-output` should be used)
openssl base64 -d -in myfile.jpg.b64 -output myfile.jpg

## decode from base64 (on Linux `-out` should be used)
openssl base64 -d -in myfile.jpg.b64 -out myfile.jpg

Omitting the -out/-output... filename will print to stdout.


Another ootb utility present both in OSX and Ubuntu:

## encode to base64
base64 < myfile.jpg > myfile.jpg.b64

## decode from base64 (OSX) (note the uppercase 'D')
base64 -D < myfile.jpg.b64 > myfile.jpg

## decode from base64 (Linux) (note the lowercase 'd')
base64 -d < myfile.jpg.b64 > myfile.jpg

In terms of speed, I would use openssl followed by perl, followed by uuencode. In terms of portability, I would use uuencode followed by Perl followed by openssl (If you care about reusing the code on as many other UNIX like stock platforms as possible). Be careful though because not all UNIX variants support the -m switch (iirc AIX does, HP/UX does, Solaris doesn't).

$ time perl -MMIME::Base64 -e 'undef $/;while(<>){print encode_base64($_);}' \
> out.jpg 1>filename.b64
real    0m0.025s

$ time uuencode -m -o filename.b64 out.jpg filename_when_uudecoded.txt
real    0m0.051s

$  time openssl base64 -in out.jpg -out filename.b64 
real    0m0.017s

Use the -m switch to uuencode file_in.txt per base64 as specified by RFC1521 and write it to filename.b64 (with filename_when_uudecoded.txt as the default filename when decoded):

uuencode -m -o filename.b64 file_in.txt filename_when_uudecoded.txt

STDIN example:

cat file_in.txt | uuencode -m -o filename.b64 filename_when_uudecoded.txt

In addition to Steve Folly's answer above, when encoding in stdin mode, to avoid passing extra newlines, press CTRL+D twice to end input without any additional newlines.
Output will show right after the same line.

For example:

$ openssl base64 Enter

Alternatively, you could use printf:

$ printf 'input' | openssl base64
  • You meant to say encoding, right?
    – nethero
    Apr 19, 2022 at 15:08
  • @nethero - yes, corrected.
    – solimant
    Apr 20, 2022 at 16:05
uuencode -m [-o output_file] [file] name

Where name is the name to display in the encoded header.


cat docbook-xsl.css | uuencode -m docbook-xsl.css


uuencode -m -o docbook-xsl.css.b64 docbook-xsl.css docbook-xsl.css
  • uuencode is not the encoding as base64
    – ccpizza
    Nov 17, 2016 at 7:27

For some reason, echo -n <data> | openssl base64 added a newline in the middle of my base64 data. I assume it was because my base64 data was really long.

Using echo -n <data> | base64 to encode and echo -n <base64-ed data> | base64 -D to decode worked fine.

  • nb: on my nix, i had to use -d echo -n c29tZXVzZXI6c29tZXBhc3N3b3Jk | base64 -d someuser:somepassword
    – mlo55
    Apr 14, 2016 at 0:07

A simple NodeJS version:

node -e "process.stdout.write(new Buffer(process.argv[1]).toString('base64'))" "Hello world!"
  • I don't think this is a better answer as openssl (and now base64) come with the OS.
    – Josh
    Mar 27, 2015 at 15:01
  • At the risk of splitting hairs — and, I’m aware that this criticism applies to a couple of the other answers, as well — the question asked how to encode a file or stdin. If I’m not mistaken, your answer shows only how to encode a string. Mar 27, 2015 at 19:00

There is Perl plus MIME::Base64:

perl -MMIME::Base64 -e 'undef $/;while(<>){print encode_base64($_);}'

This comes pre-installed. You can specify separate files on the command line (or supply the data on standard input); each file is separately encoded. You can also do:

perl -i.txt -MMIME::Base64 -e 'undef $/;while(<>){print encode_base64($_);}' file1

This backs up file1 to file1.txt, and writes the Base-64 encoded output over the original file.


recode should do the trick for you

recode ../b64 < file.txt > file.b64

recode is available for OS X via MacPorts.

  • There's nothing built in?
    – Josh
    Mar 17, 2010 at 0:24
  • @Josh - there is - openssl Mar 17, 2010 at 0:25
  • MacPorts does not come with any OS X distribution. There are plenty of other options that do. For instance just base64 command.
    – Jason S
    Sep 5, 2016 at 6:05

If you are base64 encoding a font file, you can do this:

base64 my-webfont.ttf > my-webfont.b64.ttf.txt

I use this on a Mac (10.10) all the time.

Note: There will be no linebreaks.


Cross-platform solutions

We compiled a list of cross-platform shell commands to encode a file as base64. The following commands take an input file (named deploy.key in examples) and convert it to base64 without any newline wrapping. The base64 output is printed to the terminal via stdout.

# For systems with openssl
openssl base64 -A -in=deploy.key

# For systems with Python (2 or 3) installed
python -c "import base64; print(base64.standard_b64encode(open('deploy.key', 'rb').read()).decode())"

# For Windows or Linux systems that have the GNU coreutils base64 command
base64 --wrap=1000000 deploy.key

# For macOS systems
base64 --break=1000000 deploy.key

To redirect the output to a file, append > base64-encoded.txt (using a file name of your choosing).

These commands were prototyped as part of this pull request where we wanted cross-platform shell commands to base64 encode an SSH private key to remove newlines.


There are many great answers already and mine does basically the same thing except the secret is never shown in the terminal.

I created these two aliases to encode a string from my clipboard and the encoded string is copied to my clipboard. The same applies to decoding:

alias decode='pbpaste | base64 --decode | pbcopy'
alias encode='pbpaste | base64 | pbcopy'

you can do this:

echo -n  "Hello, world" | base64

you will get SGVsbG8sIHdvcmxk .

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