How to base64 encode image in linux bash / shell

I'm trying to base64 encode an image in a shell script and put it into variable:

test="$(printf DSC_0251.JPG | base64)"
echo $test
RFNDXzAyNTEuSlBH

I've also tried something like this:

test=\`echo -ne DSC_0251.JPG | base64\`

but still with no success.

I want to do something like this:

curl -v -X POST -d '{"image":$IMAGE_BASE64,"location":$LOCATION,"time_created":$TIMECREATED}' -H 'Content-type: text/plain; charset=UTF8' http://192.168.1.1/upload

I found this http://www.zzzxo.com/q/answers-bash-base64-encode-script-not-encoding-right-12290484.html

but still have had no success.

You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.

test="$(cat DSC_0251.JPG | base64)"

However, base64 can read from the file itself:

test=$( base64 DSC_0251.JPG )

Encode

On Linux

Single line result:

base64 -w 0 DSC_0251.JPG

For HTML:

echo "data:image/jpeg;base64,$(base64 -w 0 DSC_0251.JPG)"

As file:

base64 -w 0 DSC_0251.JPG > DSC_0251.JPG.base64

In variable:

IMAGE_BASE64="$(base64 -w 0 DSC_0251.JPG)"

In variable for HTML:

IMAGE_BASE64="data:image/jpeg;base64,$(base64 -w 0 DSC_0251.JPG)"

On OSX

On OSX, the base64 binary is different, and the parameters are different. If you want to use it on OSX, you should remove -w 0.

Single line result:

base64 DSC_0251.JPG

For HTML:

echo "data:image/jpeg;base64,$(base64 DSC_0251.JPG)"

As file:

base64 DSC_0251.JPG > DSC_0251.JPG.base64

In variable:

IMAGE_BASE64="$(base64 DSC_0251.JPG)"

In variable for HTML:

IMAGE_BASE64="data:image/jpeg;base64,$(base64 DSC_0251.JPG)"

Generic OSX/Linux

As Shell Function

@base64() {
  if [[ "${OSTYPE}" = darwin* ]]; then
    # OSX
    if [ -t 0 ]; then
      base64 "$@"
    else
      cat /dev/stdin | base64 "$@"
    fi
  else
    # Linux
    if [ -t 0 ]; then
      base64 -w 0 "$@"
    else
      cat /dev/stdin | base64 -w 0 "$@"
    fi
  fi
}

# Usage
@base64 DSC_0251.JPG
cat DSC_0251.JPG | @base64

As Shell Script

Create base64.sh file with following content:

#!/usr/bin/env bash
if [[ "${OSTYPE}" = darwin* ]]; then
  # OSX
  if [ -t 0 ]; then
    base64 "$@"
  else
    cat /dev/stdin | base64 "$@"
  fi
else
  # Linux
  if [ -t 0 ]; then
    base64 -w 0 "$@"
  else
    cat /dev/stdin | base64 -w 0 "$@"
  fi
fi

Make it executable:

chmod a+x base64.sh

Usage:

./base64.sh DSC_0251.JPG
cat DSC_0251.JPG | ./base64.sh

Decode

Get you readable data back:

base64 -d DSC_0251.base64 > DSC_0251.JPG 

There is a Linux command for that: base64

base64 DSC_0251.JPG >DSC_0251.b64

To assign result to variable use

test=`base64 DSC_0251.JPG`

If you need input from termial, try this

lc=`echo -n "xxx_${yyy}_iOS" |  base64`

-n option will not input "\n" character to base64 command.

Base 64 for html:

file="DSC_0251.JPG"
type=$(identify -format "%m" "$file" | tr '[A-Z]' '[a-z]')
echo "data:image/$type;base64,$(base64 -w 0 "$file")"

To base64 it and put it in your clipboard:

file="test.docx"
base64 -w 0 $file  | xclip -selection clipboard

Please be very cautious when using echo (as many answers here), because it will add a newline character at the end, distorting your encoded string (leading to e.g. incorrect passwords) due to these ominous extra encoded characters: Cg== added at the end of the encoded string:

For example, if we have this string to encode:

$ MINIO_SECRET_KEY=VsarGnNADHGv

With `printf' it will look like this (correct):

$ AWS_SECRET_ACCESS_KEY="$(printf $MINIO_SECRET_KEY | base64)" && echo $AWS_SECRET_ACCESS_KEY
VnNhckduTkFESEd2

... but with echo like this (incorrect):

$ AWS_SECRET_ACCESS_KEY="$(echo $MINIO_SECRET_KEY | base64)" && echo $AWS_SECRET_ACCESS_KEY
VnNhckduTkFESEd2Cg==