Command line

arara is a command line tool. It can be used in a plethora of command interpreter implementations, from bash to a Windows prompt, provided that the Java runtime environment is accessible within the current session. This chapter covers the user interface design, as well as options (also known as flags or switches) that modify the underlying application behaviour.

# User interface design

The goal of a user interface design is to make the interaction as simple and efficient as possible. Good user interface design facilitates finishing the task at hand without drawing unnecessary attention to itself. We redesigned the interface in order to look more pleasant to the eye, after all, we work with TeX and friends:

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     / _` | '__/ _` | '__/ _` |
    | (_| | | | (_| | | | (_| |
     \__,_|_|  \__,_|_|  \__,_|

    Processing 'doc5.tex' (size: 285 B, last modified: 03/01/2020
    19:25:40), please wait.

    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS
    (BibTeX) The BibTeX reference management software ....... SUCCESS
    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS
    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS

    Total: 1.14 seconds

First of all, we have the nice application logo, displayed using ASCII art. The entire layout is based on monospaced font spacing, usually used in terminal prompts. Hopefully you follow the conventional use of a monospaced font in your terminal, otherwise the visual effect will not be so pleasant. First and foremost, arara displays details about the file being processed, including size and modification status:

    Processing 'doc5.tex' (size: 285 B, last modified: 03/01/2020
    19:25:40), please wait.

The list of tasks was also redesigned to be fully justified, and each entry displays both task and subtask names (the former being displayed enclosed in parentheses), besides of course the usual execution result:

    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS
    (BibTeX) The BibTeX reference management software ....... SUCCESS
    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS
    (PDFLaTeX) PDFLaTeX engine .............................. SUCCESS

As previously mentioned in Important concepts, if a task fails, arara will halt the entire execution at once and immediately report back to the user. This is an example of how a failed task looks like:

    (PDFLaTeX) PDFLaTeX engine .............................. FAILURE

Also, observe that our tool displays the execution time before terminating, in seconds. The execution time has a very simple precision, as it is meant to be easily readable, and should not be considered for command profiling.

    Total: 1.14 seconds

The tool has two execution modes: silent, which is the default, and verbose, which prints as much information about tasks as possible. When in silent mode, arara will simply display the task and subtask names, as well as the execution result. Nothing more is added to the output. For instance:

    (BibTeX) The BibTeX reference management software ....... SUCCESS

When executed in verbose mode, arara will display the underlying system command output as well, when applied. In version 4.0 of our tool, this mode was also entirely redesigned in order to avoid unnecessary clutter, so it would be easier to spot each task. For instance:

    -----------------------------------------------------------------
    (BibTeX) The BibTeX reference management software
    -----------------------------------------------------------------

    This is BibTeX, Version 0.99d (TeX Live 2020)
    The top-level auxiliary file: doc5.aux
    The style file: plain.bst
    Database file #1: mybib.bib

    --------------------------------------------------------- SUCCESS

It is important to observe that, when in verbose mode, arara can offer proper interaction if the system command requires user intervention. However, when in silent mode, the tool will simply discard this requirement and the command will almost surely fail.

# Options

In order to run arara on your TeX file, the simplest possible way is to provide the file name to the tool in your favourite command interpreter session, provided that the file has at least one directive:

    $ arara doc6.tex

From version 5.0 on, arara may receive more than one file as parameter. It will compile them sequentially (starting with the leftmost). The process fails on the first failure of these executions. For the files to be flawlessly compiled by TeX, they should be in the same working directory. If you process your files with other tools, this requirement could be lifted.

    $ arara doc20.tex doc21.tex

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    | (_| | | | (_| | | | (_| |
     \__,_|_|  \__,_|_|  \__,_|

    Processing 'doc20.tex' (size: 28 B, last modified: 02/28/2020
    07:15:02), please wait.

    (PDFTeX) PDFTeX engine .................................. SUCCESS

    Processing 'doc21.tex' (size: 28 B, last modified: 02/28/2020
    07:15:10), please wait.

    (PDFTeX) PDFTeX engine .................................. SUCCESS

    Total: 1.20 seconds

The tool has a set of command line options (also known as flags or switches) that modify the underlying execution behaviour or enhance the execution workflow. If you do not provide any parameters, arara will display the tool usage and the available options:

    $ arara
    Usage: arara [OPTIONS] file...

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      The cool TeX automation tool.

      arara executes the TeX workflow you tell it to execute. Simply specify your
      needs within your TeX file and let arara do the work. These directives
      feature conditional execution and parameter expansion.

    Options:
      -l, --log                        Generate a log output
      -v, --verbose / -s, --silent     Print the command output
      -n, --dry-run                    Go through all the motions of running a
                                       command, but with no actual calls
      -S, --safe-run                   Run in safe mode and disable potentially
                                       harmful features. Make sure your projects
                                       uses only allowed features.
      -w, --whole-file                 Extract directives in the file, not only in
                                       the header
      -p, --preamble TEXT              Set the file preamble based on the
                                       configuration file
      -t, --timeout INT                Set the execution timeout (in milliseconds)
      -L, --language TEXT              Set the application language
      -m, --max-loops INT              Set the maximum number of loops (> 0)
      -d, --working-directory PATH     Set the working directory for all tools
      -P, --call-property VALUE        Pass parameters to the application to be
                                       used within the session.
      --generate-completion [bash|zsh|fish]
                                       Generate a completion script for arara. Add
                                       'source <(arara --generate-completion
                                       <shell>)' to your shell's init file.
      -V, --version                    Show the version and exit
      -h, --help                       Show this message and exit

    Arguments:
      file  The file(s) to evaluate and process

The available options for our tool are detailed as follows. Each option contains short and long variations, which are denoted by `-o` and `--option` in the command line, respectively. Additionally, when a parameter is required by the current option, it will be denoted by `parameter` in the description.

- `-h` / `--help`: As the name indicates, this option prints the help message containing the tool usage and the list of all available options. The tool exits afterwards. When running arara without any options or a file to be processed, this is the default behaviour. This option has the highest priority over the others.

- `-w` / `--whole-file`: This option changes the mechanics of how arara extracts the directives from the code. The tool always reads from the beginning of the file until it reaches a line that is not empty and it is not a comment. However, by activating this switch, arara will extract all directives from the entire file (hence the option name). Consider the following example:

      % arara: pdftex
      Hello world.
      \bye

      % arara: pdftex

  When running arara without this option, one directive will be extracted (line 1). However, with `-w` enabled, the directives in lines 1 and 5 will be extracted. This option can also be disabled by default in the configuration file.

- `-l` / `--log`: This option enables the logging feature of our tool. All streams from all system commands will be logged and, at the end of the execution, a consolidated log file named `arara.log` will be generated. This option can also be activated by default in the configuration file. Refer to Logging for more details on the logging feature.

- `-L` / `--language`: This option sets the language of the current execution of arara according to the language code identified by the `code` value provided as the parameter. The language code tries to follow the IETF BCP 47 norm, standardized nomenclature used to classify languages. For example, this is our tool speaking Dutch:

      $ arara -L nl doc5.tex
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      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Verwerken van 'doc5.tex' (grootte: 285 B, laatst gewijzigd:
      03/01/2020 19:25:40), een ogenblik geduld.

      (PDFLaTeX) PDFLaTeX engine ............................ SUCCESVOL
      (BibTeX) The BibTeX reference management software ..... SUCCESVOL
      (PDFLaTeX) PDFLaTeX engine ............................ SUCCESVOL
      (PDFLaTeX) PDFLaTeX engine ............................ SUCCESVOL

      Totaal: 1,07 seconden

  > Navis volitans mihi anguillis plena est
  > At time of writing, arara is able to speak English, German, Dutch, Italian and Brazilian Portuguese out of the box. There is also a special dialect named Broad Norfolk, spoken by those living in the county of Norfolk in England.

  > Available languages: `en` for English, `de` for German, `en-QN` for Broad Norfolk, `it` for Italian, `nl` for Dutch, and `pt-BR` for Portuguese (BR).

  > Would you like to make arara speak your own language? Splendid! We would love to have you in the team! Just send us an electronic mail, join our dedicated chatroom or open an issue about it. The localization process is quite straightforward, we can help you. Any language is welcome!

  This option can also be specified in the configuration file. However, one can always override this setting by running the tool with an explicit `-L` option.

  > Invalid language codes
  > From version 6.0 on, if you pass an invalid language code, arara will now run in English and issue a log warning but not fail anymore. Failing due to the wrong language in the output was considered inappropriate.

- `-m` / `max-loops` `<number>`: As a means to avoid infinite iterations, arara has a predefined maximum number of loops, with the default set to 10, as a technical solution. For instance, consider the following directive:

      % arara: pdftex while true

  The `--max-loops` option is used to redefine the maximum number of loops our tool will allow for potentially infinite iterations. Any positive integer can be used as the `<number>` value for this option. An execution of the previous directive with a lower maximum number of loops is shown as follows:

      $ arara -m 2 doc8.tex
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      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Processing 'doc8.tex' (size: 45 B, last modified: 05/29/2018
      12:32:14), please wait.

      (PDFTeX) PDFTeX engine .................................. SUCCESS
      (PDFTeX) PDFTeX engine .................................. SUCCESS

      Total: 0.58 seconds

  This option can also be specified in the configuration file. However, one can always override this setting by running the tool with an explicit `-m` option.

- `-n` / `--dry-run`: This option makes arara go through all the motions of running tasks and subtasks, but with no actual calls. It is a very useful feature for testing the sequence of underlying system commands to be performed on a file. For instance, consider the following execution:

      $ arara -n doc5.tex
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      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Processing "doc5.tex" (size: 360 B, last modified: 12/28/2020
      13:03:32), please wait.

      [DR] (PDFLaTeX) PDFLaTeX engine
      -----------------------------------------------------------------
      Author: Island of TeX
      About to run: [pdflatex, doc5.tex] @ /home/paulo/Downloads

      [DR] (BibTeX) The BibTeX reference management software
      -----------------------------------------------------------------
      Author: Island of TeX
      About to run: [bibtex, doc5] @ /home/paulo/Downloads

      [DR] (PDFLaTeX) PDFLaTeX engine
      -----------------------------------------------------------------
      Author: Island of TeX
      About to run: [pdflatex, doc5.tex] @ /home/paulo/Downloads

      [DR] (PDFLaTeX) PDFLaTeX engine
      -----------------------------------------------------------------
      Author: Island of TeX
      About to run: [pdflatex, doc5.tex] @ /home/paulo/Downloads

      Total: 0.18 seconds

  Note that the rule authors are displayed (so they can be blamed in case anything goes wrong), as well as the system command to be executed. It is an interesting approach to see everything that will happen to your document and in which order.

  > Conditionals and boolean values
  > It is very important to observe that conditionals are not evaluated when our tool is executed in the `--dry-run` mode, although they are properly listed. Also, when a rule returns a boolean value, the code is executed regardless of this mode.

- `p` / `--preamble` `<name>`: Some TeX documents require the same automation steps, e.g, a set of articles. To this end, so as to avoid repeating the same preamble over and over in this specific scenario, arara has the possibility of setting predefined preambles in a special section of the configuration file identified by a unique key for later use. This command line option prepends the predefined preamble referenced by the `<name>` key to the current document and then proceeds to extract directives, as usual. For instance:

      twopdftex: |
        % arara: pdftex
        % arara: pdftex

      Hello world.
      \bye

  In this example, we have a preamble named `twopdftex` and a TeX file named `doc9.tex` with no directives. Of course, our tool will complain about missing directives, unless we deliberately inject the two directives from the predefined preamble into the current execution:

      $ arara -p twopdftex doc9.tex
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      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Processing 'doc9.tex' (size: 18 B, last modified: 05/29/2018
      14:39:21), please wait.

      (PDFTeX) PDFTeX engine .................................. SUCCESS
      (PDFTeX) PDFTeX engine .................................. SUCCESS

      Total: 0.96 seconds

  It is important to note that this is just a directive-based preamble and nothing else, so a line other than a directive is discarded. Line breaks and conditionals are supported. Trying to exploit this area for other purposes will not work.

- `-t` / `--timeout` `<number>`: This option sets an execution timeout for every task, in milliseconds. If the timeout is reached before the task ends, arara will kill it and halt the execution. Any positive integer can be used as the `<number>` value for this option. Of course, use a sensible value to allow proper time for a task to be executed. For instance, consider the following recursive call:

      % arara: pdftex
      \def\foo{\foo}
      This will go \foo forever.
      \bye

      $ arara --timeout 3000 doc9.tex
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      Processing 'doc10.tex' (size: 63 B, last modified: 05/29/2018
      15:24:06), please wait.

      (PDFTeX) PDFTeX engine .................................   ERROR

      The system command execution reached the provided timeout value
      and was aborted. If the time was way too short, make sure to
      provide a longer value. There are more details available on this
      exception:

      DETAILS ---------------------------------------------------------
      Timed out waiting for java.lang.UNIXProcess@6b53e23f to finish,
      timeout: 3000 milliseconds, executed command [pdftex, doc10.tex]

      Total: 3.37 seconds

  If left unattended, this particular execution would never finish (and probably crash the engine at a certain point), as expected by the recursive calls without a proper fixed point. The `--timeout` option was set at 3000 milliseconds and the task was aborted when the time limit was reached. Note that the tool raised an error about it.

- `d` / `--working-directory` `<path>` This option allows you to change the working directory to `<path>`. That is, the commands will run from a different directory than the directory you launched arara in. This is especially useful when calling a TeX engine as they resolve files against the working direcotry. For that reason, arara will also resolve each file you pass to it that has no absolute path against the working directory. The working directory is fixed for the whole call; passing multiple files to arara will resolve all of them against and execute all actions within that one working directory.

- `-V` / `--version`: This option, as the name indicates, prints the current version. It also prints the current revision and a list of libraries with their corresponding licenses. Finally, it simply exits the application. Note that this option has the second highest priority over the others.

- `-v` / `--verbose`: This option enables the verbose mode of arara. It also enables all streams to be flushed directly to the terminal, including potential user input interactions (the exact opposite of silent mode). This option can also be activated by default in the configuration file.

- `-s` / `--silent`: This option disables the verbose mode of arara (thus activating the default silent mode), if previously enabled by a proper configuration file (see Configuration file). It is important to note that this command line option has higher priority over the `--verbose` counterpart.

- `-S` / `--safe-run`: This option enables the safe mode of arara, protecting the system by disallowing certain user actions. Currently, the following features are restricted:

  - File lookup will only perform explicit file resolution. Wildcard filters are disabled.

  - `❖ unsafelyExecuteSystemCommand` will raise an exception and abort the run. Keep in mind that rules are still allowed to construct arbitrary commands using `Command` objects, so this restriction only disallows arbitrary system commands that would not get logged and are thus invisible to the user.

  - The `--options` parameter does not expand orb tags in any directive.

- `-P` / `--call-property` `<entry>`: This option forwards the provided `<entry>`, in the `key=value` format, to the session map. For instance, consider the following call:

      $ arara -P foo=bar hello.tex

  In a rule, you may now retrieve the value associated to the `foo` key, which is `bar`, set at runtime, by calling the following method in your code:

      getSession().get('arg:foo')

  This option may be called multiple times, as a means to provide as many data pairs as needed. Please refer to `❖ getSession` in Methods for more details.

You can combine options, use long or short variations interchangeably and write them in any order, provided that a file name is given at some point in the command line, otherwise the usage will be printed. Use the provided features in order to enhance and optimize your automation workflow.

# File name lookup

arara, as a command line application, provides support for a restricted range of file types. In particular, the tool recognizes five file types based on their extensions. These types are presented as follows, as well as the lookup order: `tex` `→` `dtx` `→` `ltx` `→` `drv` `→` `ins`.

Note that other extensions can be added through a proper mapping in the configuration file, as well as modifying the lookup order. This feature is detailed later on. arara employs the following scheme for file name lookup:

- First and foremost, if the provided file name already contains a valid extension, the tool attempts an exact match. If the file exists, it will be selected. This is the best approach if your working directory contains other files sharing the same base name.

      $ arara doc11.tex
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      Processing 'doc11.tex' (size: 34 B, last modified: 05/29/2018
      19:40:35), please wait.

      (PDFTeX) PDFTeX engine .................................. SUCCESS

      Total: 0.69 seconds

- If the provided file name has an unsupported extension or no extension at all, the tool iterates through the list of default extensions, appending the current element to the file name and attempting an exact match. If the file exists, it will be selected.

      $ arara doc11
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       / _` | '__/ _` | '__/ _` |
      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Processing 'doc11.tex' (size: 34 B, last modified: 05/29/2018
      19:40:35), please wait.

      (PDFTeX) PDFTeX engine .................................. SUCCESS

      Total: 0.69 seconds

- Many shells complete file names that have multiple extensions in the same directory, so that they end with a period. We try to resolve against them as well!

      $ arara doc11.
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       / _` | '__/ _` | '__/ _` |
      | (_| | | | (_| | | | (_| |
       \__,_|_|  \__,_|_|  \__,_|

      Processing 'doc11.tex' (size: 34 B, last modified: 05/29/2018
      19:40:35), please wait.

      (PDFTeX) PDFTeX engine .................................. SUCCESS

      Total: 0.69 seconds

It is highly recommended to use complete file names with our tool, in order to ensure the correct file is being processed. If your command line interpreter features tab completion, you can use it to automatically fill partially typed file names from your working directory.

> Exit status support
> arara follows the good practices of software development and provides three values for exit status, so our tool can be programmatically used in scripts and other complex workflows: `0` `→` successful execution, `1` `→` one of the rules failed, and `2` `→` an exception was raised.

> Please refer to the documentation of your favourite command line interpreter to learn more about exit status captures. Programming languages also offer methods for retrieving such information.