barcode

Encode

Generate PNG from string

barcode -b '0123456789abcdABCD' -e code128 -g 400x225 -u pt -E | magick - -background white -alpha remove -alpha off out.png

-b: string to encode (use input file if missing)
-e: encoding type (default is best fit for first string)
-g: geometry on the page: [x][++]; Note that an additional white margin of 10 points is added to the printout.
-u: unit ("mm", "in", ...)
-E: print one code as eps file (default: multi-page ps)

Generate SVG from string svgo is optional to reduce the size of the generated image. Be careful though, it might break the output!

barcode -b 'andreas-mausch.de' -e code128 -g 400x225 -u pt -S | svgo - > out.svg

Decode

via zbarimg

zbarimg code.png

Encoding types

Known encodings are (synonyms appear on the same line):
        "ean", "ean13", "ean-13", "ean8", "ean-8"
        "upc", "upc-a", "upc-e"
        "isbn"
        "39", "code39"
        "39ext", "code39ext"
        "128c", "code128c"
        "128b", "code128b"
        "128", "code128"
        "128raw"
        "i25", "interleaved 2 of 5"
        "cbr", "codabar"
        "msi"
        "pls", "plessey"
        "code93", "93"
        "code11", "11"

Code39 vs. Code128

A Code 128 barcode can encode a full 128 ASCII character set. A Code 39 barcode encodes 39 characters in total.

Code 128 has a higher density than Code 39.

Code 39 does not include a check digit, while Code 128 does. – https://www.dynamsoft.com/blog/insights/code-39-vs-code-128/

Differences between Code128 A, B, C

128A (Code Set A) – ASCII characters 00 to 95 (0–9, A–Z and control codes), special characters, and FNC 1–4

128B (Code Set B) – ASCII characters 32 to 127 (0–9, A–Z, a–z), special characters, and FNC 1–4

128C (Code Set C) – 00–99 (encodes two digits with a single code point) and FNC1 – https://en.wikipedia.org/wiki/Code_128#Subtypes

So if your string only contains digits, you can use Set C to save some space.

Error correction and checksum

Code128 does have a checksum character, while Code39 does not. However, neither has any type of error correction with redundant data, like in QR codes.