How to use base64 encoded image as an argument?

Question

I am trying to use the base64 encoding of an image as a flag when I run my program. Im getting back: Argument list too long

I am on a Ubuntu 16.04 Docker image on a mac.

$ ./myProgram -input "/9j/4AAQSkZJRgABA [...]"

This might help you: https://stackoverflow.com/questions/19354870/bash-command-line-and-input-limit — user3486184, Mar 27 '19 at 21:34
The image can't be bigger than 96kb (Linux) or 192kb (mac), because this would base64 encode to the argument limit of 128kb/256kb — that other guy, Mar 27 '19 at 21:39
Can you read it through stdin instead? That would avoid any issues with the size of the argument. — John Szakmeister, Mar 27 '19 at 21:41

score 0 · Answer 1 · answered Mar 28 '19 at 01:16

There is a length limit of a single command. This is your program... It should be easier in every way to send the name of the file as the argument to your program which would then read the desired information from the file. You could cat the contents of the file into a variable (if you really want it as a variable). It may be more conventional if you passed the contents of the file to your program via the standard input stream.

score 0 · Accepted Answer · answered Mar 28 '19 at 01:48

Instead of accepting it as an argument, I would suggest you read it from standard in instead.

$ base64 someImage.jpg | ./myProgram

If this program is a shell script, you can save standard in into a variable with something like this:

#!/bin/sh

MY_BASE64_IMAGE_INPUT=$(cat -)
# do something with that info
echo $MY_BASE64_IMAGE_INPUT

How to use base64 encoded image as an argument?

2 Answers2