command-line.rst

QR Code creation from the command line

The command line script segno can be used to print QR codes to the terminal or to save them in supported formats like SVG, PNG, EPS, …, see CLI man page <man/segno> for details

By default, the script does not create Micro QR codes, use --micro <segno --micro> to allow the creation of Micro QR codes or specify the version (like --version=M3 <segno --version>) to create a Micro QR Code.

See the CLI man page <man/segno> for a detailed reference of all command line options.

Usage

Output the QR code to the terminal:

$ segno "Little wing"

Same content, but as Micro QR code (M4):

$ segno --micro "Little wing"

Using a more compact representation of the code:

$ segno --compact "Little wing"

QR Code version

If the --version <segno --version> / -v <segno -v> parameter is not provided, Segno chooses the minimal version for the QR code automatically. The version may be specified as an integer or as Micro QR Code identifier.

The content 'Layla' would fit into a 1-H QR code, but the following commands enforce version 5:

$ segno --version=5 Layla
$ segno -v=5 Layla

Micro QR Code:

$ segno -v m4 Layla
$ segno --version M4 Layla

QR Code error correction level

The default error correction level is "L" (or any better if --no-error-boost <segno --no-error-boost> was not set, c.f. boost-error-correction-level), use the --error <segno --error> / -e <segno -e> parameter to change it:

$ segno --error=q "Ain't no grave"
$ segno -e=h "Heart of Gold"

QR code serialization

Printing the QR code to the terminal is nice but the --output <segno --output> / -o <segno -o> parameter serializes the QR code in one of the supported file formats:

$ segno --output=white-room.png "White Room"

$ segno -o=satellite.svg "Satellite Of Love"

$ segno --output=mrs.eps "Mrs. Robinson"
$ segno --output=dedodo.pdf "De Do Do Do, De Da Da Da"
$ segno --output=tin-pan-alley.svgz "Tin Pan Alley"

$ segno --output=thrill-gone.txt "The Thrill Is Gone"

Scaling QR codes

If the resulting QR code is too small, --scale <segno --scale> or -s <segno -s> can be used to create a more appropriate output:

$ segno --scale=10 --output=money-talks.png "Money Talks"

$ segno -s 10 --output=private-investigations.svg Private Investigations

If the serializer does not support a scaling factor (i.e. text output), this parameter is ignored.

Changing the size of the quiet zone

The generated QR code will have a recommended quiet zone / border around the symbol. To change the size of the border, --border <segno --border> or the shortcut -b <segno -b> can be utilized:

$ segno --border 0 --scale 4 --output=black-magic-woman.svg "Black Magic Woman"

$ segno --border 10 --scale 4 --output diamond.png "Shine On You Crazy Diamond"

$ segno -b 30 --scale 4 --output=boom-boom.svg Boom Boom

Colors

Usually, all QR codes are serialized in black and white. Use --dark <segno --dark> to change the color of the dark modules and --light <segno --light> to change the color of the light modules.

Change the color of the dark modules to to darkblue:

$ segno --dark=darkblue --scale 4 --output=excited.png "So Excited"

Change the color of the light modules to transparent:

$ segno --light=transparent --scale 4 --output=hotel.png "Hotel California"

Change the color of the dark modules to darkblue and the color of the light modules to yellow:

$ segno --dark=darkblue --light=yellow --scale 4 --output=dontgiveup.svg "Don't Give Up"

If the serializer does not support --color <segno --dark> or --light <segno --light>, these arguments are ignored.

The SVG <svg>, PNG <png> and PPM <ppm> serializers support more than two colors, each module type (finder pattern (dark / light), alignment pattern (dark / light) etc.) may have its own color, see colorful-qrcodes for details.

$ segno --dark darkred --data-dark darkorange --data-light yellow --scale 5 -o qrcode_yellow-submarine.png Yellow Submarine

Structured Append

The Structured Append <structured-append> mode can be used to split a message across multiple (max. 16) QR codes.

To create a sequence of QR codes, the --seq <segno --seq> argument must be provided. Additionally, either the --version <segno --version> or the desired number of symbols (--symbol-count <segno --symbol-count>) must be provided:

$ segno --seq -v 1 --scale 3 -o polythene-pam.png "Well you should see Polythene Pam"

Specify the max. number of symbols:

$ segno --seq --symbol-count=2 -s 3 -o sa_yellow-submarine.png "We all live in a yellow submarine"

Shortcut to specify the number of symbols:

$ segno --seq -sc 2 -s 3 -o julia.png "Half of what I say is meaningless"