Change the usage misnomer to "description" (#13598)

# Description
    
The meaning of the word usage is specific to describing how a command
function is *used* and not a synonym for general description. Usage can
be used to describe the SYNOPSIS or EXAMPLES sections of a man page
where the permitted argument combinations are shown or example *uses*
are given.
Let's not confuse people and call it what it is a description.

Our `help` command already creates its own *Usage* section based on the
available arguments and doesn't refer to the description with usage.

# User-Facing Changes

`help commands` and `scope commands` will now use `description` or
`extra_description`
`usage`-> `description`
`extra_usage` -> `extra_description`

Breaking change in the plugin protocol:

In the signature record communicated with the engine.
`usage`-> `description`
`extra_usage` -> `extra_description`

The same rename also takes place for the methods on
`SimplePluginCommand` and `PluginCommand`

# Tests + Formatting
- Updated plugin protocol specific changes
# After Submitting
- [ ] update plugin protocol doc

crates/nu-command/src/bytes/add.rs

@@ -51,7 +51,7 @@ impl Command for BytesAdd {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Add specified bytes to the input."
     }
 

crates/nu-command/src/bytes/at.rs

@@ -53,7 +53,7 @@ impl Command for BytesAt {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Get bytes defined by a range."
     }
 

crates/nu-command/src/bytes/build_.rs

@@ -8,7 +8,7 @@ impl Command for BytesBuild {
         "bytes build"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Create bytes from the arguments."
     }
 

crates/nu-command/src/bytes/bytes_.rs

@@ -14,11 +14,11 @@ impl Command for Bytes {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Various commands for working with byte data."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }
 

crates/nu-command/src/bytes/collect.rs

@@ -20,7 +20,7 @@ impl Command for BytesCollect {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Concatenate multiple binary into a single binary, with an optional separator between each."
     }
 

crates/nu-command/src/bytes/ends_with.rs

@@ -41,7 +41,7 @@ impl Command for BytesEndsWith {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Check if bytes ends with a pattern."
     }
 

crates/nu-command/src/bytes/index_of.rs

@@ -47,7 +47,7 @@ impl Command for BytesIndexOf {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Returns start index of first occurrence of pattern in bytes, or -1 if no match."
     }
 

crates/nu-command/src/bytes/length.rs

@@ -29,7 +29,7 @@ impl Command for BytesLen {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Output the length of any bytes in the pipeline."
     }
 

crates/nu-command/src/bytes/remove.rs

@@ -40,7 +40,7 @@ impl Command for BytesRemove {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Remove bytes."
     }
 

crates/nu-command/src/bytes/replace.rs

@@ -41,7 +41,7 @@ impl Command for BytesReplace {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Find and replace binary."
     }
 

crates/nu-command/src/bytes/reverse.rs

@@ -25,7 +25,7 @@ impl Command for BytesReverse {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Reverse the bytes in the pipeline."
     }
 

crates/nu-command/src/bytes/starts_with.rs

@@ -39,7 +39,7 @@ impl Command for BytesStartsWith {
             .category(Category::Bytes)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Check if bytes starts with a pattern."
     }
 

crates/nu-command/src/charting/histogram.rs

@@ -26,7 +26,7 @@ impl Command for Histogram {
             .category(Category::Chart)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a new table with a histogram based on the column name passed in."
     }
 

crates/nu-command/src/conversions/fill.rs

@@ -32,7 +32,7 @@ impl Command for Fill {
         "fill"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Fill and Align."
     }
 

crates/nu-command/src/conversions/into/binary.rs

@@ -43,7 +43,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to a binary primitive."
     }
 

crates/nu-command/src/conversions/into/bool.rs

@@ -29,7 +29,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to boolean."
     }
 

crates/nu-command/src/conversions/into/cell_path.rs

@@ -25,7 +25,7 @@ impl Command for IntoCellPath {
             .allow_variants_without_examples(true)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to a cell-path."
     }
 
@@ -33,7 +33,7 @@ impl Command for IntoCellPath {
         vec!["convert"]
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "Converting a string directly into a cell path is intentionally not supported."
     }
 

crates/nu-command/src/conversions/into/command.rs

@@ -14,11 +14,11 @@ impl Command for Into {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Commands to convert data from one type to another."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }
 

crates/nu-command/src/conversions/into/datetime.rs

@@ -145,7 +145,7 @@ impl Command for SubCommand {
         }
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert text or timestamp into a datetime."
     }
 

crates/nu-command/src/conversions/into/duration.rs

@@ -36,11 +36,11 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to duration."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "Max duration value is i64::MAX nanoseconds; max duration time unit is wk (weeks)."
     }
 

crates/nu-command/src/conversions/into/filesize.rs

@@ -51,7 +51,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to filesize."
     }
 

crates/nu-command/src/conversions/into/float.rs

@@ -32,7 +32,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert data into floating point number."
     }
 

crates/nu-command/src/conversions/into/glob.rs

@@ -39,7 +39,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to glob."
     }
 

crates/nu-command/src/conversions/into/int.rs

@@ -89,7 +89,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to integer."
     }
 

crates/nu-command/src/conversions/into/record.rs

@@ -21,7 +21,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to record."
     }
 

crates/nu-command/src/conversions/into/string.rs

@@ -60,7 +60,7 @@ impl Command for SubCommand {
             .category(Category::Conversions)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert value to string."
     }
 

crates/nu-command/src/conversions/into/value.rs

@@ -31,7 +31,7 @@ impl Command for IntoValue {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Infer nushell datatype for each cell."
     }
 

crates/nu-command/src/database/commands/into_sqlite.rs

@@ -46,7 +46,7 @@ impl Command for IntoSqliteDb {
         operate(engine_state, stack, call, input)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert table into a SQLite database."
     }
 

crates/nu-command/src/database/commands/query_db.rs

@@ -27,7 +27,7 @@ impl Command for QueryDb {
             .category(Category::Database)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Query a database using SQL."
     }
 

crates/nu-command/src/database/commands/schema.rs

@@ -17,7 +17,7 @@ impl Command for SchemaDb {
             .category(Category::Database)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Show the schema of a SQLite database."
     }
 

crates/nu-command/src/date/date_.rs

@@ -14,11 +14,11 @@ impl Command for Date {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Date-related commands."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }
 

crates/nu-command/src/date/humanize.rs

@@ -21,7 +21,7 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Print a 'humanized' format for the date, relative to now."
     }
 

crates/nu-command/src/date/list_timezone.rs

@@ -15,7 +15,7 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "List supported time zones."
     }
 

crates/nu-command/src/date/now.rs

@@ -15,7 +15,7 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Get the current date."
     }
 

crates/nu-command/src/date/to_record.rs

@@ -20,7 +20,7 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert the date into a record."
     }
 

crates/nu-command/src/date/to_table.rs

@@ -20,7 +20,7 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert the date into a structured table."
     }
 

crates/nu-command/src/date/to_timezone.rs

@@ -19,11 +19,11 @@ impl Command for SubCommand {
             .category(Category::Date)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Convert a date to a given time zone."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "Use 'date list-timezone' to list all supported time zones."
     }
 

crates/nu-command/src/debug/ast.rs

@@ -10,7 +10,7 @@ impl Command for Ast {
         "ast"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Print the abstract syntax tree (ast) for a pipeline."
     }
 

crates/nu-command/src/debug/debug_.rs

@@ -8,7 +8,7 @@ impl Command for Debug {
         "debug"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Debug print the value(s) piped in."
     }
 

crates/nu-command/src/debug/explain.rs

@@ -12,7 +12,7 @@ impl Command for Explain {
         "explain"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Explain closure contents."
     }
 

crates/nu-command/src/debug/info.rs

@@ -20,11 +20,11 @@ impl Command for DebugInfo {
         "debug info"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "View process memory info."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "This command is meant for debugging purposes.\nIt shows you the process information and system memory information."
     }
 

crates/nu-command/src/debug/inspect.rs

@@ -10,7 +10,7 @@ impl Command for Inspect {
         "inspect"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Inspect pipeline results while running a pipeline."
     }
 

crates/nu-command/src/debug/metadata.rs

@@ -12,7 +12,7 @@ impl Command for Metadata {
         "metadata"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Get the metadata for items in the stream."
     }
 

crates/nu-command/src/debug/metadata_set.rs

@@ -9,7 +9,7 @@ impl Command for MetadataSet {
         "metadata set"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Set the metadata for items in the stream."
     }
 

crates/nu-command/src/debug/profile.rs

@@ -43,11 +43,11 @@ impl Command for DebugProfile {
             .category(Category::Debug)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Profile pipeline elements in a closure."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"The profiler profiles every evaluated pipeline element inside a closure, stepping into all
 commands calls and other blocks/closures.
 

crates/nu-command/src/debug/timeit.rs

@@ -9,7 +9,7 @@ impl Command for TimeIt {
         "timeit"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Time the running time of a block."
     }
 

crates/nu-command/src/debug/view.rs

@@ -14,11 +14,11 @@ impl Command for View {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Various commands for viewing debug information."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }
 

crates/nu-command/src/debug/view_files.rs

@@ -8,11 +8,11 @@ impl Command for ViewFiles {
         "view files"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "View the files registered in nushell's EngineState memory."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "These are files parsed and loaded at runtime."
     }
 

crates/nu-command/src/debug/view_ir.rs

@@ -29,11 +29,11 @@ impl Command for ViewIr {
             .category(Category::Debug)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "View the compiled IR code for a block of code."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "
 The target can be a closure, the name of a custom command, or an internal block
 ID. Closure literals within IR dumps often reference the block by ID (e.g.

crates/nu-command/src/debug/view_source.rs

@@ -11,7 +11,7 @@ impl Command for ViewSource {
         "view source"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "View a block, module, or a definition."
     }
 

crates/nu-command/src/debug/view_span.rs

@@ -8,11 +8,11 @@ impl Command for ViewSpan {
         "view span"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "View the contents of a span."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "This command is meant for debugging purposes.\nIt allows you to view the contents of nushell spans.\nOne way to get spans is to pipe something into 'debug --raw'.\nThen you can use the Span { start, end } values as the start and end values for this command."
     }
 

crates/nu-command/src/env/config/config_.rs

@@ -14,11 +14,11 @@ impl Command for ConfigMeta {
             .input_output_types(vec![(Type::Nothing, Type::String)])
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Edit nushell configuration files."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "You must use one of the following subcommands. Using this command as-is will only produce this help message."
     }
 

crates/nu-command/src/env/config/config_env.rs

@@ -19,7 +19,7 @@ impl Command for ConfigEnv {
         // TODO: Signature narrower than what run actually supports theoretically
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Edit nu environment configurations."
     }
 

crates/nu-command/src/env/config/config_nu.rs

@@ -23,7 +23,7 @@ impl Command for ConfigNu {
         // TODO: Signature narrower than what run actually supports theoretically
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Edit nu configurations."
     }
 

crates/nu-command/src/env/config/config_reset.rs

@@ -22,7 +22,7 @@ impl Command for ConfigReset {
             .category(Category::Env)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Reset nushell environment configurations to default, and saves old config files in the config location as oldconfig.nu and oldenv.nu."
     }
 

crates/nu-command/src/env/export_env.rs

@@ -20,11 +20,11 @@ impl Command for ExportEnv {
             .category(Category::Env)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Run a block and preserve its environment in a current scope."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"This command is a parser keyword. For details, check:
   https://www.nushell.sh/book/thinking_in_nu.html"#
     }

crates/nu-command/src/env/load_env.rs

@@ -8,7 +8,7 @@ impl Command for LoadEnv {
         "load-env"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Loads an environment update from a record."
     }
 

crates/nu-command/src/env/source_env.rs

@@ -25,11 +25,11 @@ impl Command for SourceEnv {
             .category(Category::Core)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Source the environment from a source file into the current environment."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"This command is a parser keyword. For details, check:
   https://www.nushell.sh/book/thinking_in_nu.html"#
     }

crates/nu-command/src/env/with_env.rs

@@ -25,7 +25,7 @@ impl Command for WithEnv {
             .category(Category::Env)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Runs a block with an environment variable set."
     }
 

crates/nu-command/src/experimental/is_admin.rs

@@ -8,7 +8,7 @@ impl Command for IsAdmin {
         "is-admin"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Check if nushell is running with administrator or root privileges."
     }
 

crates/nu-command/src/filesystem/cd.rs

@@ -10,7 +10,7 @@ impl Command for Cd {
         "cd"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Change directory."
     }
 

crates/nu-command/src/filesystem/du.rs

@@ -27,7 +27,7 @@ impl Command for Du {
         "du"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Find disk usage sizes of specified items."
     }
 

crates/nu-command/src/filesystem/glob.rs

@@ -44,7 +44,7 @@ impl Command for Glob {
             .category(Category::FileSystem)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a list of files and/or folders based on the glob pattern provided."
     }
 
@@ -114,7 +114,7 @@ impl Command for Glob {
         ]
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"For more glob pattern help, please refer to https://docs.rs/crate/wax/latest"#
     }
 

crates/nu-command/src/filesystem/ls.rs

@@ -38,7 +38,7 @@ impl Command for Ls {
         "ls"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "List the filenames, sizes, and modification times of items in a directory."
     }
 

crates/nu-command/src/filesystem/mktemp.rs

@@ -10,7 +10,7 @@ impl Command for Mktemp {
         "mktemp"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Create temporary files or directories using uutils/coreutils mktemp."
     }
 

crates/nu-command/src/filesystem/open.rs

@@ -18,11 +18,11 @@ impl Command for Open {
         "open"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Load a file into a cell, converting to table if possible (avoid by appending '--raw')."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "Support to automatically parse files with an extension `.xyz` can be provided by a `from xyz` command in scope."
     }
 

crates/nu-command/src/filesystem/rm.rs

@@ -25,7 +25,7 @@ impl Command for Rm {
         "rm"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Remove files and directories."
     }
 

crates/nu-command/src/filesystem/save.rs

@@ -22,7 +22,7 @@ impl Command for Save {
         "save"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Save a file."
     }
 

crates/nu-command/src/filesystem/start.rs

@@ -15,7 +15,7 @@ impl Command for Start {
         "start"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Open a folder, file or website in the default application or viewer."
     }
 

crates/nu-command/src/filesystem/touch.rs

@@ -51,7 +51,7 @@ impl Command for Touch {
             .category(Category::FileSystem)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates one or more files."
     }
 

crates/nu-command/src/filesystem/ucp.rs

@@ -20,7 +20,7 @@ impl Command for UCp {
         "cp"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Copy files using uutils/coreutils cp."
     }
 

crates/nu-command/src/filesystem/umkdir.rs

@@ -28,7 +28,7 @@ impl Command for UMkdir {
         "mkdir"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Create directories, with intermediary directories if required using uutils/coreutils mkdir."
     }
 

crates/nu-command/src/filesystem/umv.rs

@@ -14,7 +14,7 @@ impl Command for UMv {
         "mv"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Move files or directories using uutils/coreutils mv."
     }
 

crates/nu-command/src/filesystem/watch.rs

@@ -28,7 +28,7 @@ impl Command for Watch {
         "watch"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Watch for file changes and execute Nu code when they happen."
     }
 

crates/nu-command/src/filters/all.rs

@@ -20,7 +20,7 @@ impl Command for All {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Test if every element of the input fulfills a predicate expression."
     }
 

crates/nu-command/src/filters/any.rs

@@ -20,7 +20,7 @@ impl Command for Any {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Tests if any element of the input fulfills a predicate expression."
     }
 

crates/nu-command/src/filters/append.rs

@@ -20,11 +20,11 @@ impl Command for Append {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Append any number of rows to a table."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"Be aware that this command 'unwraps' lists passed to it. So, if you pass a variable to it,
 and you want the variable's contents to be appended without being unwrapped, it's wise to
 pre-emptively wrap the variable in a list, like so: `append [$val]`. This way, `append` will

crates/nu-command/src/filters/chunks.rs

@@ -20,11 +20,11 @@ impl Command for Chunks {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Divide a list or table into chunks of `chunk_size`."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "This command will error if `chunk_size` is negative or zero."
     }
 

crates/nu-command/src/filters/columns.rs

@@ -17,11 +17,11 @@ impl Command for Columns {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Given a record or table, produce a list of its columns' names."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "This is a counterpart to `values`, which produces a list of columns' values."
     }
 

crates/nu-command/src/filters/compact.rs

@@ -27,7 +27,7 @@ impl Command for Compact {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Creates a table with non-empty rows."
     }
 

crates/nu-command/src/filters/default.rs

@@ -26,7 +26,7 @@ impl Command for Default {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Sets a default value if a row's column is missing or null."
     }
 

crates/nu-command/src/filters/drop/column.rs

@@ -24,7 +24,7 @@ impl Command for DropColumn {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Remove N columns at the right-hand end of the input table. To remove columns by name, use `reject`."
     }
 

crates/nu-command/src/filters/drop/drop_.rs

@@ -21,7 +21,7 @@ impl Command for Drop {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Remove items/rows from the end of the input list/table. Counterpart of `skip`. Opposite of `last`."
     }
 

crates/nu-command/src/filters/drop/nth.rs

@@ -27,7 +27,7 @@ impl Command for DropNth {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Drop the selected rows."
     }
 

crates/nu-command/src/filters/each.rs

@@ -10,11 +10,11 @@ impl Command for Each {
         "each"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Run a closure on each row of the input list, creating a new list with the results."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"Since tables are lists of records, passing a table into 'each' will
 iterate over each record, not necessarily each cell within it.
 

crates/nu-command/src/filters/enumerate.rs

@@ -8,7 +8,7 @@ impl Command for Enumerate {
         "enumerate"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Enumerate the elements in a stream."
     }
 

crates/nu-command/src/filters/every.rs

@@ -27,7 +27,7 @@ impl Command for Every {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Show (or skip) every n-th row, starting from the first one."
     }
 

crates/nu-command/src/filters/filter.rs

@@ -10,11 +10,11 @@ impl Command for Filter {
         "filter"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Filter values based on a predicate closure."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"This command works similar to 'where' but allows reading the predicate closure from
 a variable. On the other hand, the "row condition" syntax is not supported."#
     }

crates/nu-command/src/filters/find.rs

@@ -57,7 +57,7 @@ impl Command for Find {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Searches terms in the input."
     }
 

crates/nu-command/src/filters/first.rs

@@ -31,7 +31,7 @@ impl Command for First {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Return only the first several rows of the input. Counterpart of `last`. Opposite of `skip`."
     }
 

crates/nu-command/src/filters/flatten.rs

@@ -28,7 +28,7 @@ impl Command for Flatten {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Flatten the table."
     }
 

crates/nu-command/src/filters/get.rs

@@ -8,11 +8,11 @@ impl Command for Get {
         "get"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Extract data using a cell path."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"This is equivalent to using the cell path access syntax: `$env.OS` is the same as `$env | get OS`.
 
 If multiple cell paths are given, this will produce a list of values."#

crates/nu-command/src/filters/group.rs

@@ -23,7 +23,7 @@ impl Command for Group {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Groups input into groups of `group_size`."
     }
 

crates/nu-command/src/filters/group_by.rs

@@ -34,7 +34,7 @@ impl Command for GroupBy {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Splits a list or table into groups, and returns a record containing those groups."
     }
 

crates/nu-command/src/filters/headers.rs

@@ -22,7 +22,7 @@ impl Command for Headers {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Use the first row of the table as column names."
     }
 

crates/nu-command/src/filters/insert.rs

@@ -33,11 +33,11 @@ impl Command for Insert {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Insert a new column, using an expression or closure to create each row's values."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "When inserting a column, the closure will be run for each row, and the current row will be passed as the first argument.
 When inserting into a specific index, the closure will instead get the current value at the index or null if inserting at the end of a list/table."
     }

crates/nu-command/src/filters/interleave.rs

@@ -10,11 +10,11 @@ impl Command for Interleave {
         "interleave"
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Read multiple streams in parallel and combine them into one stream."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         r#"This combinator is useful for reading output from multiple commands.
 
 If input is provided to `interleave`, the input will be combined with the

crates/nu-command/src/filters/is_empty.rs

@@ -20,7 +20,7 @@ impl Command for IsEmpty {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Check for empty values."
     }
 

crates/nu-command/src/filters/is_not_empty.rs

@@ -20,7 +20,7 @@ impl Command for IsNotEmpty {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Check for non-empty values."
     }
 

crates/nu-command/src/filters/items.rs

@@ -22,11 +22,11 @@ impl Command for Items {
             .category(Category::Filters)
     }
 
-    fn usage(&self) -> &str {
+    fn description(&self) -> &str {
         "Given a record, iterate on each pair of column name and associated value."
     }
 
-    fn extra_usage(&self) -> &str {
+    fn extra_description(&self) -> &str {
         "This is a the fusion of `columns`, `values` and `each`."
     }