Linux Command - "base64"

Data Encoding Tutorials - Herong's Tutorial Examples

∟Linux Command - "base64"

This section provides a tutorial example on how to use 'base64' command on a Linux system to perform Base64 encoding and decoding.

If you are using a Linux system, you can use the built-in command "base64" to perform Base64 encoding and decoding.

Here is the manual page for "base64":

herong$ man base64

NAME
  base64 - base64 encode/decode data and print to standard output

SYNOPSIS
  base64 [OPTION]... [FILE]

DESCRIPTION
  Base64 encode or decode FILE, or standard input, to standard output.

  -w, --wrap=COLS
        Wrap encoded lines after COLS character (default 76).  
        Use 0 to disable line wrapping.

  -d, --decode
        Decode data.

  -i, --ignore-garbage
        When decoding, ignore non-alphabet characters.

  --help display this help and exit

  --version
        output version information and exit

  With no FILE, or when FILE is -, read standard input.

  The  data  are  encoded as described for the base64 alphabet in RFC 3548.
  When decoding, the input may contain newlines in addition to the bytes of
  the  formal  base64  alphabet. Use --ignore-garbage to attempt to recover
  from any other non-alphabet bytes in the encoded stream.

AUTHOR  
  Written by Simon Josefsson.

Test 1 - Let's encode a short text string of "ABC" from a file, which can be created using the "cat > input.txt" command. We need to press Ctrl-D and Ctrl-C to end the input stream from the keyboard.

herong$ cat > input.txt
ABC^D^C

herong$ base64 < input.txt
QUJD

Test 2 - Let's decode a short encoded string of "QUJD" back.

herong$ base64 < input.txt > output.txt

herong$ more output.txt
QUJD

herong$ base64 -d < output.txt > decoded.txt 

herong$ more decoded.txt
ABC

Test 3 - Let's encode the "lazy dog" message:

herong$ more lazy_dog.txt
The quick brown fox jumps over the lazy dog.

herong$ base64 < lazy_dog.txt
VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZy4=

Test 4 - Let's encode a binary file. The output is wrapped into 76-character lines to meet the MIME (Multipurpose Internet Mail Extensions) specification.

herong$ curl http://herongyang.com/_logo.png > icon.png  

herong$ base64 < icon.png 

iVBORw0KGgoAAAANSUhEUgAAABgAAAAYCAYAAADgdz34AAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAAEnQAABJ0Ad5mH3gAAAEYSURBVEhL7ZbLDcIwDIYdBGfYADahm1E24QRr
9AxLNBvAuUjgJE7ruI5S8RAXPslqaltxfsdSax4IfJEZPQeMSa2EyLdmTwHCKUhwLmYt1BTIIPIl
eovkyZUUj8zrrgDzJb0EQovuN64SbFt7d4/cCLE2bYWFCsxi2e9xutxCwOvormOV3OEMcxJkXLiO
55A/vuSIy+MsVrTA0+5TRfbQ0ErBl9EUIO2hGpxobUUXznzeCO6KCkI0U8DDA5oxuLvcooibjAy2
Zq3BQdEoF8CxsxWtBevdllZ51AJx1KJtGlQtwU4keTiiGmUFGdymU3i5wFTUAuk8BJOMcrpXL/lN
/gWKfK6A+A5EpheQYzORr7foB38VHwXgCfzQYOFCEQYGAAAAAElFTkSuQmCC

Test 4 - Let's to stop wrapping with the "-w 0" option:

herong$ base64 -w 0 < icon.png 

iVBORw0KGgoAAAANSUhEUgAAABgAAAAY ... HwXgCfzQYOFCEQYGAAAAAElFTkSuQmCC

Table of Contents

About This Book

Base64 Encoding

►Base64 Encoding and Decoding Tools

Base64.Guru - Base64 Online Tool

Windows Command - "certutil -encode/-decode"

►Linux Command - "base64"

macOS Command - "base64"

Java Built-In Implementation of Base64

Java Built-In Implementation of MIME Base64

Python Built-In Implementation of Base64

Python Built-In Implementation of MIME Base64

PHP Built-In Implementation of Base64

PHP Built-In Implementation of MIME Base64

Perl Built-In Implementation of Base64

Perl Built-In Implementation of MIME Base64

Base64URL - URL Safe Base64 Encoding

Base32 Encoding

URL Encoding, URI Encoding, or Percent Encoding

UUEncode Encoding

References

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