Add examples for env,let-env,rm,touch and date list-timezone (#4531)

* feat: update #4518, add examples for env,let-env,rm,touch and date list-timezone

* fix typo

* update example for `date list-timezone` command

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

@@ -1,7 +1,9 @@
 use chrono_tz::TZ_VARIANTS;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, IntoInterruptiblePipelineData, PipelineData, Signature, Value};
+use nu_protocol::{
+    Category, Example, IntoInterruptiblePipelineData, PipelineData, Signature, Span, Value,
+};
 
 #[derive(Clone)]
 pub struct SubCommand;
@@ -41,4 +43,19 @@ impl Command for SubCommand {
             .into_iter()
             .into_pipeline_data(engine_state.ctrlc.clone()))
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            example: "date list-timezone | where timezone =~ Shanghai",
+            description: "Show timezone(s) that contains 'Shanghai'",
+            result: Some(Value::List {
+                vals: vec![Value::Record {
+                    cols: vec!["timezone".into()],
+                    vals: vec![Value::test_string("Asia/Shanghai")],
+                    span: Span::test_data(),
+                }],
+                span: Span::test_data(),
+            }),
+        }]
+    }
 }

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

@@ -1,7 +1,7 @@
 use nu_engine::env_to_string;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, IntoPipelineData, PipelineData, Signature, Value};
+use nu_protocol::{Category, Example, IntoPipelineData, PipelineData, Signature, Value};
 
 #[derive(Clone)]
 pub struct Env;
@@ -59,4 +59,24 @@ impl Command for Env {
 
         Ok(Value::List { vals: values, span }.into_pipeline_data())
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Display current path environment variable",
+                example: "env | where name == PATH",
+                result: None,
+            },
+            Example {
+                description: "Check whether the env variable `MY_ENV_ABC` exists",
+                example: r#"env | any? name == MY_ENV_ABC"#,
+                result: Some(Value::test_bool(false)),
+            },
+            Example {
+                description: "Another way to check whether the env variable `PATH` exists",
+                example: r#"'PATH' in (env).name"#,
+                result: Some(Value::test_bool(true)),
+            },
+        ]
+    }
 }

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

@@ -1,7 +1,7 @@
 use nu_engine::{current_dir, eval_expression_with_input, CallExt};
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, PipelineData, Signature, SyntaxShape, Value};
+use nu_protocol::{Category, Example, PipelineData, Signature, SyntaxShape, Value};
 
 #[derive(Clone)]
 pub struct LetEnv;
@@ -58,4 +58,12 @@ impl Command for LetEnv {
         }
         Ok(PipelineData::new(call.head))
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Create an environment variable and display it",
+            example: "let-env MY_ENV_VAR = 1; $env.MY_ENV_VAR",
+            result: Some(Value::test_int(1)),
+        }]
+    }
 }

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

@@ -12,8 +12,8 @@ use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
-    Category, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span, Spanned,
-    SyntaxShape, Type, Value,
+    Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span,
+    Spanned, SyntaxShape, Type, Value,
 };
 
 const GLOB_PARAMS: glob::MatchOptions = glob::MatchOptions {
@@ -67,6 +67,31 @@ impl Command for Rm {
     ) -> Result<PipelineData, ShellError> {
         rm(engine_state, stack, call)
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Delete or move a file to the system trash (depending on 'rm_always_trash' config option)",
+                example: "rm file.txt",
+                result: None,
+            },
+            Example {
+                description: "Move a file to the system trash",
+                example: "rm --trash file.txt",
+                result: None,
+            },
+            Example {
+                description: "Delete a file permanently",
+                example: "rm --permanent file.txt",
+                result: None,
+            },
+            Example {
+                description: "Delete a file, and suppress errors if no file is found",
+                example: "rm --force file.txt",
+                result: None,
+            }
+        ]
+    }
 }
 
 fn rm(

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

@@ -3,7 +3,7 @@ use std::fs::OpenOptions;
 use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, PipelineData, ShellError, Signature, SyntaxShape};
+use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, SyntaxShape};
 
 #[derive(Clone)]
 pub struct Touch;
@@ -52,4 +52,19 @@ impl Command for Touch {
 
         Ok(PipelineData::new(call.head))
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Creates \"fixture.json\"",
+                example: "touch fixture.json",
+                result: None,
+            },
+            Example {
+                description: "Creates files a, b and c",
+                example: "touch a b c",
+                result: None,
+            },
+        ]
+    }
 }