Ruby TTY::Option localization means helping people understand a Ruby command-line program’s positional arguments, named options, flags, keywords and environment-based settings without inventing commands that the parser cannot accept. People looking for TTY::Option DSL, Ruby CLI multilingual help, option validation, parameter conversion or Unicode terminal errors need to know which words are software tokens and which messages can safely be translated.
Consider a read-only field survey tool that lets a volunteer preview observations before exporting them. The program accepts a survey identifier, a –limit option and possibly a value from an environment variable. A volunteer reading in Portuguese should know the order of those inputs, which values are required, where defaults come from and how to recover if a path contains spaces. Localized descriptions are useful only when they reflect the actual TTY::Option parser definitions.
This guide builds from that ordinary example to explain TTY::Option’s argument, keyword, option, flag and environment declarations, its params interface, generated help and parsing errors. It then shows how to design an application-controlled translation layer, test Unicode examples across shells and judge real user success. The purpose is clear educational guidance, not the claim that including a gem automatically translates every message.
Quick answer: what to localize and what to keep literal
- Keep registered commands, flags, stable data keys, accepted values and exit semantics accurate.
- Translate reader-facing descriptions, task guidance, application messages and recovery steps as complete natural sentences.
- Check working commands, printed help and failure messages in the version actually shipped.
- Use harmless test fixtures, Unicode input and an independent reader to verify that the explanation leads to a correct action.
Start with the real command rather than a translated guess
TTY::Option is a Ruby library for parsing command-line arguments, options, keywords and environment variables. It exposes a declaration DSL and parameter access so applications can describe input contracts in one place. That is especially helpful for translation because a writer can map each user-visible explanation to a specific declared input. But a declared parameter name may also be part of application code; it is not inherently safe to rewrite as prose.
The project documentation describes generated help, type conversion, help customization and collected parsing errors. Those features can make a CLI approachable, but they do not eliminate design questions: which language does the program use, which defaults are safe, how does it report an invalid value, and do command examples match the installed gem? Those questions need deliberate testing rather than assumptions about terminal support.
Use a read-only survey preview as a learning model. The program should state exactly which survey it will inspect and how many records it intends to display. Keep the parsing layer and action layer separate: first verify what the library returns, then design localized display sentences. That separation makes it possible to translate messages without corrupting input keys, environment variable names or machine-readable results.
A small, read-only Ruby TTY::Option example
# Illustrative structure; check your installed tty-option version.
require "tty-option"
class Preview
include TTY::Option
argument :survey, required: true
option :limit, type: :integer, default: 10
flag :verbose
def call
values = params
puts "Survey=#{values[:survey]} limit=#{values[:limit]}"
end
end
# Application launcher should invoke the documented parser entry point
# for the installed version before calling its read-only action.The declaration names in this Ruby sketch illustrate three different input contracts: a required positional value, a typed named option and a Boolean flag. The exact parse invocation and applicable DSL settings should be taken from the gem version your application uses, not guessed from another Ruby CLI framework. Test the parser before writing translated command examples; treat custom output sentences as separate catalog entries.
The practical field guide: Ruby TTY::Option localization decisions
1. Module and DSL contract
What the software and the language each do. Including TTY::Option introduces a parameter declaration interface to a Ruby class; it does not make every method name into a public option or translate the application’s own prose automatically.
Example for a reader. A survey preview object declares what it can accept before its read-only action runs, making support messages easier to connect to a particular input definition. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Inspect the generated help from the installed gem and compare every advertised parameter with the exact class declaration rather than a writer’s assumptions. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
2. Positional argument declaration
What the software and the language each do. The argument DSL records input that appears by position, so its order and requiredness are part of the executable command contract rather than discretionary wording.
Example for a reader. A volunteer enters survey-2026 as the first value; the guide must not suggest that the survey identifier can appear after arbitrary switches without testing parser behavior. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run empty, one-value and several-value invocations and inspect where the parser places each result in params. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
3. Keyword parameters
What the software and the language each do. The keyword DSL is a distinct way to declare named inputs, and it should not be confused with a Ruby method’s keyword arguments or a shell environment variable.
Example for a reader. A developer names a keyword output in code while the translator writes a longer explanation of what the selected value changes. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Compare the actual accepted form, returned params key and generated help before publishing examples in another language. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
4. Options with values
What the software and the language each do. An option may consume an argument, making its value placeholder and conversion rule as important as its visible name.
Example for a reader. The –limit option receives a count; writing that it is a simple yes-or-no switch causes the next token to be swallowed or ignored. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test an absent limit, a valid integer, a nonnumeric string and an unexpectedly large value, and inspect the parser’s actual error. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
5. Boolean flags
What the software and the language each do. A flag indicates presence or absence, and its semantics should be explained without telling users to enter an extra localized affirmative word.
Example for a reader. A beginner might type –verbose sim where the program actually accepts only –verbose; the description should explain the effect, not prescribe a value. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run the invocation with and without the flag and compare both parsed results and output behavior. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
6. Environment variables
What the software and the language each do. TTY::Option can declare values from an environment source, but shell syntax for setting those variables depends on platform and the application contract.
Example for a reader. A survey identifier comes from SURVEY_ID in a noninteractive deployment; instructions written for Bash cannot simply be pasted into PowerShell unchanged. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test a missing variable, an empty variable and a valid variable in each supported platform shell; state precedence based on observed behavior. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
7. Defaults and absent input
What the software and the language each do. A default is different from a user-supplied value, especially when a default may be overridden by an option or environment setting.
Example for a reader. A read-only preview defaults to ten rows; a translated sentence must not imply that ten is the maximum the software can ever display. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Compare omitted, explicitly supplied and environment-influenced values and show which one takes precedence in the actual program. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
8. Required values
What the software and the language each do. Requiredness turns a hint into a validation rule; readers need to understand what must be entered before an action can start.
Example for a reader. A volunteer sees a friendly translated description of the survey name but overlooks that it is mandatory and blames an empty preview on missing data. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run without the required input and check that the error identifies a concrete remedy and an accepted command form. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
9. Conversion to integers
What the software and the language each do. Type conversion changes the parsed Ruby value and can reject locale-specific number spellings not supported by the converter.
Example for a reader. A translated guide uses 1,000 as a count, but the parser may expect 1000 without punctuation; the result is a failure unrelated to language proficiency. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test zero, negatives, grouping separators, native digits and invalid text and document only formats the installed converter accepts. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
10. List and repeated inputs
What the software and the language each do. A list-like parameter needs explicit guidance on separators, repeats and quoting, because different CLI frameworks have different conventions.
Example for a reader. A field worker wants to preview two survey IDs and assumes commas are accepted because the translated instructions show an English list separated by commas. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Observe whether the parser creates one string, several entries or an error, then document the supported syntax with a runnable example. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
11. Map values
What the software and the language each do. A map parameter may parse keys and values with a structured separator; translating data keys silently can break downstream decisions.
Example for a reader. A team sets region=west for a reporting filter but the translated document changes region into a localized field name that application logic does not recognize. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test exact key separators, quoting and duplicate keys, and distinguish stable machine keys from explanatory labels. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
12. Named parameter collisions
What the software and the language each do. Two declarations that appear distinct to a reader may normalize to the same key or conflict with a short form, making aliases a software design issue.
Example for a reader. A future short option is introduced and shadows an existing shorthand; the localized quick-start continues to recommend the old one. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Enumerate visible names and alias spellings, then run conflict tests before accepting a newly proposed translated shortcut. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
13. Short and long option forms
What the software and the language each do. Short forms are convenient but often cryptic; help should explain the same operation for both spellings without promising one that is not registered.
Example for a reader. The program accepts –verbose and -v; the translated guide can use the long form in its main example and mention -v as the exact alternative. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run every form and confirm the same parsed value; favor the explicit long spelling for introductory documentation. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
14. Generated help headings
What the software and the language each do. The library can generate usage and help from definitions, but the displayed prose is only as accurate as the declarations and supplied descriptions.
Example for a reader. A volunteer who sees three settings under one large heading needs to distinguish a positional survey identifier from output settings. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Capture generated help at a comfortable and narrow terminal width, then edit confusing descriptions at their actual source. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
15. Usage customization
What the software and the language each do. Header, examples and related usage methods can make the help more task-oriented, but they should not contradict generated parameter expectations.
Example for a reader. A translated header promises a read-only survey preview while a later example uses an unrelated export command; the mismatch undermines trust. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Compare each customized section with the actual action, checking that command examples are copyable and not merely conceptual illustrations. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
16. Environment naming conventions
What the software and the language each do. Environment variable identifiers are normally literal keys in a process environment; translating their names in prose does not create corresponding variables.
Example for a reader. Documentation describes SURVEY_ID in English and wrongly replaces it with an accented identifier in Portuguese while the application still reads SURVEY_ID. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Set exactly the published variable name in a fresh process and confirm the app receives it in every target locale. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
17. Configuration precedence
What the software and the language each do. When CLI options and environment values both exist, which wins should be established from the library and the program instead of inferred from naming conventions.
Example for a reader. A deployment sets LIMIT=50 but a user passes –limit 5, expecting the more explicit command-line choice to control the preview. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run a precedence matrix and print parsed values in a harmless test build so documentation can state the observed result accurately. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
18. Parameter access through params
What the software and the language each do. The params collection holds resolved values for application use; its keys form a developer interface that translators should not casually rename.
Example for a reader. A Ruby action reads params[:survey] and params[:limit]; the translated help text can be elegant without changing those lookup symbols. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test expected keys and types after valid parsing, before testing localized result sentences and templates. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
19. Missing values versus empty strings
What the software and the language each do. An absent field, an empty string and a whitespace-only string may trigger different validation paths, so a general message such as ‘incorrect data’ is rarely enough.
Example for a reader. A survey identifier is supplied as an empty quoted argument; the parser may accept its shape while domain validation later rejects it. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Write a separate error message for each meaningful failure, and confirm the next-step instruction matches where validation occurred. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
20. Error collection
What the software and the language each do. Collected parsing errors offer an opportunity to show several issues coherently, but an application must avoid dumping technical internals without guidance.
Example for a reader. A volunteer misses the survey and supplies an invalid count; showing only a stack trace makes it impossible to know which problem to correct first. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test simultaneous failures and inspect ordering, display and exit behavior under non-English messages. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
21. Converting custom types
What the software and the language each do. Custom conversion can help with dates or formats, but a human explanation should state the accepted format and timezone rather than guess regional conventions.
Example for a reader. A field review expects an ISO date, while a translator substitutes a local numeric date whose day and month order is ambiguous. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test documented examples through the actual converter and ensure translated text shows one unambiguous valid format. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
22. Validation order
What the software and the language each do. Syntactic parsing, conversion and business validation can run at different times; the guide should separate mistakes in the command from missing survey data.
Example for a reader. The parser accepts a survey ID but the database has no record of it; the error must say the survey is unavailable rather than blame a flag. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Classify failures by phase and verify each translated error points to a realistic next action. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
23. Help for global parameters
What the software and the language each do. Global settings that apply across commands need a stable explanation and a consistent location in help, especially when inheritance is used.
Example for a reader. A parent class defines a shared verbosity option; a child command’s local help should not hide or redefine it unpredictably. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Check root and child help, then confirm a global value reaches each intended action in the parsed params. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
24. Inheritance of declarations
What the software and the language each do. Parameter inheritance can reduce duplication but also makes the source of a setting less obvious to a reader reviewing child commands.
Example for a reader. A developer adds an audit mode in the parent class, unexpectedly exposing it in several otherwise read-only tools. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Inspect the full resolved parameter list for every public command and remove risky inherited switches only through an approved software change. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
25. Localization catalogs
What the software and the language each do. A Ruby translation mechanism such as I18n is an application decision; TTY::Option declarations do not automatically provide full multilingual output.
Example for a reader. A team stores help descriptions and domain errors in separate locale files while keeping –limit and code-side params keys literal. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Resolve the intended language before populating user-visible descriptions, and exercise a missing translation key and fallback language. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
26. Sentence placeholders
What the software and the language each do. Translating complete sentences with placeholders is safer than joining word fragments in English order, because syntax changes between languages.
Example for a reader. The result says ‘Previewed 1 entry’ or ‘Previewed 7 entries’; other languages may require distinct plural forms and different placement of the count. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Test zero, one and several rows, checking accents, grammatical order and whether the actual number remains readable. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
27. Unicode paths
What the software and the language each do. Ruby strings can carry Unicode but filesystem names, shell quoting and terminal rendering are separate systems that may fail independently.
Example for a reader. A survey file is stored under a directory with Japanese characters and spaces, and a script works in an IDE but not when invoked from a shell. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Use a real temporary Unicode path and test parsing, existence checks and error display rather than treating correct string output as sufficient. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
28. Bidirectional scripts
What the software and the language each do. Arabic and Hebrew help may combine right-to-left sentences with left-to-right command tokens, confusing visual order if examples are not tested.
Example for a reader. A reader copies –limit 5 from within an Arabic instruction; the token must remain logically intact even if punctuation appears reversed. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Inspect the rendered help and the pasted command as separate artifacts; isolate technical tokens in documentation where possible. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
29. Non-interactive mode
What the software and the language each do. Some CLI tools run in automated environments without an interactive terminal, so localization should not require a prompt merely to choose a language.
Example for a reader. A nightly preview job has no standard input; an added language selector blocks execution even though every required value was supplied. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Support an explicit locale option or environment setting when appropriate and test execution with standard input closed. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
30. Exit codes
What the software and the language each do. A localized error should preserve the process status automation expects, even when its explanatory sentences change.
Example for a reader. A shell script relies on failure detection; a translated warning that exits successfully can silently mark incomplete survey previews as completed. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run valid, invalid and help invocations as subprocesses and check both streams and status codes. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
31. Terminal column width
What the software and the language each do. A narrow terminal can turn attractive generated help into unreadable overlapping columns, especially for translated text and wide characters.
Example for a reader. A volunteer uses a remote terminal on a small laptop and finds the long option explanations wrapping in the middle of the parameter name. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Capture help at several widths and shorten only descriptions that are redundant, retaining required input guidance. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
32. Accessibility and plain text
What the software and the language each do. Color, icons and alignment can help some readers but cannot be the only way to distinguish errors or required inputs.
Example for a reader. A monochrome screen reader reads only the textual output; a red error indicator without a descriptive sentence communicates nothing useful. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Disable decorative styling in a test run and ask whether the text alone identifies the problem, expected input and remedy. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
33. Packaging and gem dependencies
What the software and the language each do. A developer’s checkout can load translation catalogs and runtime dependencies that the released gem or command package does not contain.
Example for a reader. A clean installation prints English because locale files were omitted from the package even though local tests had been green. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Install the artifact into a clean environment and check help, errors and Unicode data without relying on source-tree paths. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
34. Supported Ruby versions
What the software and the language each do. Language and gem versions can influence parser behavior, encodings and help layout, so generic examples should name what has been tested.
Example for a reader. A library update changes conversion behavior and an old guide implies that a value form is still supported without verification. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Run a small supported-version matrix and review upstream release notes when upgrading the parser. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
35. Security and secrets
What the software and the language each do. Error messages should not echo private survey tokens or environment secrets for the sake of translated diagnostics.
Example for a reader. A user mistypes an API token; an unredacted error includes the full supplied value in a shared terminal log. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Use harmless test credentials and inspect error, debug and verbose paths, redacting sensitive parameters before release. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
36. Consumer success as the test
What the software and the language each do. A guide is successful when someone unfamiliar with the Ruby implementation can complete one valid task and recover independently from a mistake.
Example for a reader. Give a first-time user a survey name and ask them to preview five rows, inspect help and correct an invalid count in their own language. A good guide gives the reader a specific value to supply, says what the command will do with it, and distinguishes the program’s accepted spelling from the translated explanation.
How to check and repair it. Record the command they actually use and revise instructions that cause hesitation, rather than relying on developer familiarity. Compare a working case with one predictable failure and one boundary case. That three-part comparison helps identify whether the difficulty is command syntax, application logic, input encoding or an unclear sentence.
Three longer case studies: apply the rules in the field
1. A field survey translated into Portuguese
A nonprofit builds a read-only tool for checking whether a survey batch exists and how many entries it contains. In Portuguese help, staff can see the purpose of each parameter, but the first draft invents a translated version of –limit. Testing exposes that it is not registered. The team fixes the explanation, not the software token, and adds one copyable command. It then tests the default count and a nonnumeric input, making each error identify both a cause and a remedy. Volunteers who do not know Ruby can now preview a batch without needing a developer.
2. A Unicode file name fails only in production
An English-language laptop can load a survey whose file path contains Latin letters, but a Japanese field office stores inputs in folders with Japanese names and spaces. The first support reply assumes translation encoding is the cause. A careful test separates shell quoting, Ruby parameter parsing, filesystem access and terminal display. The program already preserves the parameter correctly; the real problem is a deployment path assumption. Help is updated with correctly quoted examples and clear troubleshooting steps, while stable input tokens are retained.
3. A misleading inheritance rule reaches child commands
A parent command class defines a shared setting that appears unexpectedly in several child commands. A translation review notices that one child description says the setting is available, while the other language’s help omits it. Instead of editing one sentence only, the team examines resolved parameter declarations in the installed gem, confirms the desired scope with product owners and tests the complete command tree. It then localizes the same source of truth for each supported language, including failure recovery and machine output stability.
A repeatable multilingual acceptance test
A strong Ruby TTY::Option translation is not simply a file full of translated strings. It is an interaction that can be completed correctly. Begin with an ordinary reader task and an exact executable. Record the version, terminal, locale, actual command, parsed values, visible output and exit code. Change one language variable at a time. If a failure occurs, ask whether the reader copied a real flag, misunderstood the position of an argument, supplied an unsupported format, or encountered a missing resource. Each explanation requires a different correction.
- Capture root help and every supported child command’s help, including headings, examples and default values.
- Run one successful read-only invocation in each locale, recording exact tokens and parsed results.
- Run a missing-required-input case and verify that the error identifies a copyable correction.
- Run an invalid-value case; check typed parsing, validation advice, stderr and nonzero exit status when appropriate.
- Check spaces, Unicode filenames, diacritics, combining marks and bidirectional punctuation where relevant.
- Inspect both a wide terminal and a narrow one, plus output redirected to a file without interactive styling.
- Build or install the real distributable artifact from a clean environment so translations do not depend on developer paths.
- Keep machine-readable output and accepted command tokens stable unless a deliberate, versioned software change says otherwise.
- Ask an independent reader to complete the task and recover from one mistake using only the published help.
Vocabulary that makes CLI translation easier
- Command
- An executable route recognized by the program; its translated description is not necessarily an accepted alias.
- Option or flag
- A named input, sometimes a switch and sometimes a key that consumes a value. The registered spelling is part of the interface.
- Positional argument
- An input whose location in the command matters. Natural-language word order does not redefine this location.
- Default
- The value used when an input is omitted, which can differ from a mandatory value and from a maximum limit.
- Locale
- A language and regional context for messages and formats; it does not automatically translate machine identifiers.
- Fallback
- The deliberate behavior when a translated message is unavailable. It should preserve meaning rather than silently lose essential instructions.
- Exit code
- The machine-readable result of command success or failure, which must remain dependable for scripts.
- Copyable example
- A tested command using an actual registered route and representative harmless input, not a decorative approximation.
Frequently asked questions
Does including TTY::Option translate a Ruby CLI?
No. The library defines and parses inputs. The application must decide where translated descriptions, usage guidance and domain error messages come from and how fallbacks behave.
What are the main parameter kinds?
The project’s DSL includes arguments, options, flags, keywords and environment values. Each kind has different syntax and behavior, so do not describe them all as interchangeable flags.
Should params keys change with language?
Generally not. They are part of code-side interfaces. Keep keys and registered option names stable while translating human explanations unless the software explicitly supports localized aliases.
Can help text be customized?
Yes. The project documents customization facilities for help and usage output. Verify the installed version and ensure every customized example matches a real parser invocation.
What if a local numeric format is rejected?
Do not claim a format is accepted because it is familiar to the reader. Test conversion rules, show one valid literal form, and if necessary implement a separate robust locale-aware converter.
How do environment variables work?
Treat an environment variable name as an exact identifier. Check where the library reads it, what happens when it is missing and whether it overrides an explicitly supplied option.
Why is an error different from missing survey data?
Missing or malformed command arguments are parsing problems; a valid identifier that does not exist is a domain problem. Translate both but give different recovery steps.
How do I test Arabic help?
Capture text in a real bidirectional terminal, copy tokens into a fresh shell and verify that flags, punctuation, counts and path names remain unambiguous.
How do I prevent breaking automation?
Keep machine keys and exit semantics stable. Provide structured output for scripts, and localize human-facing explanations instead of output that another program parses.
What is the first useful exercise?
Make a read-only preview with one required argument, one typed option and one flag. Document three successful examples and three failures, then test the same task with a second locale.
Four-week practical learning and release plan
Week 1 — map the actual executable
Create a small read-only fixture and record the installed library version, all registered commands, input contracts and generated usage. Capture successful and failing invocations before translating any prose. For each displayed token, mark whether it is a literal command, a placeholder, a value, a sentence or an output field. This inventory prevents friendly translations from becoming false instructions.
Week 2 — write complete human-facing explanations
Prepare natural descriptions, complete output sentences and recovery messages in the intended languages. Preserve commands and values unless software deliberately registers aliases. Include the meaning of defaults, ranges, optional inputs and quoting. Use target-language reviewers who understand the reader’s task but do not need to inspect the implementation. Check fallback behavior with one deliberately missing harmless catalog entry.
Week 3 — test boundaries, packaging and Unicode
Run copied commands under target locales and realistic shells, exercising Unicode paths, spaces, negative and invalid values, missing arguments and terminal width. Capture all output and status codes. Install the distributable artifact in a clean environment and confirm the language resources are actually present. Keep separate checks for machine-consumed output, since a polished translated message can otherwise break automation.
Week 4 — independent completion and maintenance
Give a reader the guide and ask them to finish a task, interpret one failure and retry without a developer. Observe where they hesitate and correct the exact wording or example. Rebuild help snapshots and retest after changing a command, dependency or message catalog. Keep a short release record containing tested locales, commands and unresolved limitations so future updates have a clear baseline.
Final checklist: meaning and executable truth
The practical standard for Ruby TTY::Option is independent completion. A reader should know what command to type, which part of the input is a value, why an option is available, what output to expect, and how to recover if the command is refused. The best translation makes technical syntax less intimidating without falsifying it. Keep the scope of the program modest when teaching, use real fixtures, explain the boundary between parser and application, and document any feature you have not tested as conditional rather than universal.