# Command line interface¶

The command line interface utility for AiiDA is called verdi. This section explains the basic concepts that apply to all verdi commands.

## Parameters¶

Parameters to verdi commands come in two flavors:

• Arguments: positional parameters, e.g. 123 in verdi process kill 123

• Options: announced by a flag (e.g. -f or --flag), potentially followed by a value. E.g. verdi process list --limit 10 or verdi process -h.

### Multi-value options¶

Some verdi commands provide options that can take multiple values. This allows to avoid repetition and e.g. write:

verdi export create -N 10 11 12 -- archive.aiida


verdi export create -N 10 -N 11 -N 12 archive.aiida


Note the use of the so-called ‘endopts’ marker -- that is necessary to mark the end of the -N option and distinguish it from the archive.aiida argument.

## Help strings¶

Append the --help option to any verdi (sub-)command to get help on how to use it. For example, verdi process kill --help shows:

Usage: verdi process kill [OPTIONS] [PROCESSES]...

Kill running processes.

Options:
-t, --timeout FLOAT  Time in seconds to wait for a response before timing
out.  [default: 5.0]
--wait / --no-wait   Wait for the action to be completed otherwise return as
soon as it's scheduled.
-h, --help           Show this message and exit.


All help strings consist of three parts:

• A Usage: line describing how to invoke the command

• A description of the command’s functionality

• A list of the available options

The Usage: line encodes information on the command’s parameters, e.g.:

• [OPTIONS]: this command takes one (or more) options

• PROCESSES: this command requires a process as a positional argument

• [PROCESSES]: this command takes a process as an optional positional argument

• [PROCESSES]...: this command takes one or more processes as optional positional arguments

Multi-value options are followed by ... in the help string and the Usage: line of the corresponding command will contain the ‘endopts’ marker. For example:

Usage: verdi export create [OPTIONS] [--] OUTPUT_FILE

Export various entities, such as Codes, Computers, Groups and Nodes, to an
archive file for backup or sharing purposes.

Options:
-X, --codes CODE...             one or multiple codes identified by their
ID, UUID or label
-Y, --computers COMPUTER...     one or multiple computers identified by
their ID, UUID or label
-G, --groups GROUP...           one or multiple groups identified by their
ID, UUID or name
-N, --nodes NODE...             one or multiple nodes identified by their ID
or UUID
...


## Profile¶

AiiDA supports multiple profiles per installation, one of which is marked as the default and used unless another profile is requested. Show the current default profile using:

verdi profile list


In order to use a different profile, pass the -p/--profile option to any verdi command, for example:

verdi -p <profile> process list


Note that the specified profile will be used for this and only this command. Use verdi profile setdefault in order to permanently change the default profile.

## Identifiers¶

When working with AiiDA entities, you need a way to refer to them on the command line. Any entity in AiiDA can be addressed via three identifiers:

• “Primary Key” (PK): An integer, e.g. 723, identifying your entity within your database (automatically assigned)

• Universally Unique Identifier (UUID): A string, e.g. ce81c420-7751-48f6-af8e-eb7c6a30cec3 identifying your entity globally (automatically assigned)

• Label: A human-readable string, e.g. test_calculation (manually assigned)

Note

PKs are easy to type and work as long as you stay within your database. When sharing data with others, however, always use UUIDs.

Any verdi command that expects an identifier as a paramter will accept PKs, UUIDs and labels.

In almost all cases, this will work out of the box. Since command line parameters are passed as strings, AiiDA needs to deduce the type of identifier from its content, which can fail in edge cases (see Implementation of identifier resolution for details). You can take the following precautions in order to avoid such edge cases:

• PK: no precautions needed

• UUID: no precautions needed for full UUIDs. Partial UUIDs should include at least one non-numeric character or dash

• Label: add an exclamation mark ! at the end of the identifier in order to force interpretation as a label

### Implementation of identifier resolution¶

The logic for deducing the identifier type is as follows:

1. Try interpreting the identifier as a PK (integer)

2. If this fails, try interpreting the identifier as a UUID (full or partial)

3. If this fails, interpret the identifier as a label

The following example illustrates edge cases that can arise in this logic:

PK

UUID

LABEL

10

group

11

10

12

3df34a1e-5215-4e1a-b626-7f75b9586ef5

• trying to identify the first entity by its partial UUID 12 would match the third entity by its PK instead
• trying to identify the second entity by its label 10 would match the first entity by its PK instead
• trying to identify the third entity by its label deadbeef would match the second entity on its partial UUID deadbeef instead
The case of a label being also a valid PK or (partial) UUID requires a different solution. For this case, verdi reserves a special character, the exclamation mark !, that can be appended to the identifier. Before any type guessing is done, AiiDA checks for the presence of this marker and, if found, will interpret the identifier as a label. I.e. to solve ambiguity examples mentioned above, one would pass 10! and deadbeef!.