diff --git a/crates/nu-command/src/default_context.rs b/crates/nu-command/src/default_context.rs
index 6b372f444d..4110e72999 100644
--- a/crates/nu-command/src/default_context.rs
+++ b/crates/nu-command/src/default_context.rs
@@ -104,6 +104,7 @@ pub fn create_default_context() -> EngineState {
             StrContains,
             StrDowncase,
             StrEndswith,
+            StrIndexOf,
             StrFindReplace,
             StrKebabCase,
             StrPascalCase,
diff --git a/crates/nu-command/src/strings/str_/index_of.rs b/crates/nu-command/src/strings/str_/index_of.rs
new file mode 100644
index 0000000000..40ae8e0389
--- /dev/null
+++ b/crates/nu-command/src/strings/str_/index_of.rs
@@ -0,0 +1,413 @@
+use nu_engine::CallExt;
+use nu_protocol::ast::Call;
+use nu_protocol::ast::CellPath;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::Spanned;
+use nu_protocol::{Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Value};
+use std::sync::Arc;
+
+struct Arguments {
+    end: bool,
+    pattern: String,
+    range: Option<Value>,
+    column_paths: Vec<CellPath>,
+}
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+#[derive(Clone)]
+pub struct IndexOfOptionalBounds(i32, i32);
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "str index-of"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("str index-of")
+            .required(
+                "pattern",
+                SyntaxShape::String,
+                "the pattern to find index of",
+            )
+            .rest(
+                "rest",
+                SyntaxShape::CellPath,
+                "optionally returns index of pattern in string by column paths",
+            )
+            .named(
+                "range",
+                SyntaxShape::Any,
+                "optional start and/or end index",
+                Some('r'),
+            )
+            .switch("end", "search from the end of the string", Some('e'))
+    }
+
+    fn usage(&self) -> &str {
+        "Returns starting index of given pattern in string counting from 0. Returns -1 when there are no results."
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        operate(engine_state, stack, call, input)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Returns index of pattern in string",
+                example: " 'my_library.rb' | str index-of '.rb'",
+                result: Some(Value::test_int(10)),
+            },
+            Example {
+                description: "Returns index of pattern in string with start index",
+                example: " '.rb.rb' | str index-of '.rb' -r '1,'",
+                result: Some(Value::test_int(3)),
+            },
+            Example {
+                description: "Returns index of pattern in string with end index",
+                example: " '123456' | str index-of '6' -r ',4'",
+                result: Some(Value::test_int(-1)),
+            },
+            Example {
+                description: "Returns index of pattern in string with start and end index",
+                example: " '123456' | str index-of '3' -r '1,4'",
+                result: Some(Value::test_int(2)),
+            },
+            Example {
+                description: "Alternatively you can use this form",
+                example: " '123456' | str index-of '3' -r [1 4]",
+                result: Some(Value::test_int(2)),
+            },
+            Example {
+                description: "Returns index of pattern in string",
+                example: " '/this/is/some/path/file.txt' | str index-of '/' -e",
+                result: Some(Value::test_int(18)),
+            },
+        ]
+    }
+}
+
+fn operate(
+    engine_state: &EngineState,
+    stack: &mut Stack,
+    call: &Call,
+    input: PipelineData,
+) -> Result<PipelineData, ShellError> {
+    let pattern: Spanned<String> = call.req(engine_state, stack, 0)?;
+
+    let options = Arc::new(Arguments {
+        pattern: pattern.item,
+        range: call.get_flag(engine_state, stack, "range")?,
+        end: call.has_flag("end"),
+        column_paths: call.rest(engine_state, stack, 1)?,
+    });
+    let head = call.head;
+    input.map(
+        move |v| {
+            if options.column_paths.is_empty() {
+                action(&v, &options, head)
+            } else {
+                let mut ret = v;
+                for path in &options.column_paths {
+                    let opt = options.clone();
+                    let r = ret.update_cell_path(
+                        &path.members,
+                        Box::new(move |old| action(old, &opt, head)),
+                    );
+                    if let Err(error) = r {
+                        return Value::Error { error };
+                    }
+                }
+                ret
+            }
+        },
+        engine_state.ctrlc.clone(),
+    )
+}
+
+fn action(
+    input: &Value,
+    Arguments {
+        ref pattern,
+        range,
+        end,
+        ..
+    }: &Arguments,
+    head: Span,
+) -> Value {
+    let range = match range {
+        Some(range) => range.clone(),
+        None => Value::String {
+            val: "".to_string(),
+            span: head,
+        },
+    };
+
+    let r = process_range(input, &range, head);
+
+    match input {
+        Value::String { val: s, .. } => {
+            let (start_index, end_index) = match r {
+                Ok(r) => (r.0 as usize, r.1 as usize),
+                Err(e) => return Value::Error { error: e },
+            };
+
+            if *end {
+                if let Some(result) = s[start_index..end_index].rfind(&**pattern) {
+                    Value::Int {
+                        val: result as i64 + start_index as i64,
+                        span: head,
+                    }
+                } else {
+                    Value::Int {
+                        val: -1,
+                        span: head,
+                    }
+                }
+            } else if let Some(result) = s[start_index..end_index].find(&**pattern) {
+                Value::Int {
+                    val: result as i64 + start_index as i64,
+                    span: head,
+                }
+            } else {
+                Value::Int {
+                    val: -1,
+                    span: head,
+                }
+            }
+        }
+        other => Value::Error {
+            error: ShellError::UnsupportedInput(
+                format!(
+                    "Input's type is {}. This command only works with strings.",
+                    other.get_type()
+                ),
+                Span::unknown(),
+            ),
+        },
+    }
+}
+
+fn process_range(
+    input: &Value,
+    range: &Value,
+    head: Span,
+) -> Result<IndexOfOptionalBounds, ShellError> {
+    let input_len = match input {
+        Value::String { val: s, .. } => s.len(),
+        _ => 0,
+    };
+    let min_index_str = String::from("0");
+    let max_index_str = input_len.to_string();
+    let r = match range {
+        Value::String { val: s, .. } => {
+            let indexes: Vec<&str> = s.split(',').collect();
+
+            let start_index = indexes.get(0).unwrap_or(&&min_index_str[..]).to_string();
+
+            let end_index = indexes.get(1).unwrap_or(&&max_index_str[..]).to_string();
+
+            Ok((start_index, end_index))
+        }
+        Value::List { vals, .. } => {
+            if vals.len() > 2 {
+                Err(ShellError::UnsupportedInput(
+                    String::from("there shouldn't be more than two indexes. too many indexes"),
+                    head,
+                ))
+            } else {
+                let idx: Vec<String> = vals
+                    .iter()
+                    .map(|v| v.as_string().unwrap_or_else(|_| String::from("")))
+                    .collect();
+
+                let start_index = idx.get(0).unwrap_or(&min_index_str).to_string();
+                let end_index = idx.get(1).unwrap_or(&max_index_str).to_string();
+
+                Ok((start_index, end_index))
+            }
+        }
+        other => Err(ShellError::UnsupportedInput(
+            format!(
+                "Input's type is {}. This command only works with strings.",
+                other.get_type()
+            ),
+            head,
+        )),
+    }?;
+
+    let start_index = r.0.parse::<i32>().unwrap_or(0);
+    let end_index = r.1.parse::<i32>().unwrap_or(input_len as i32);
+
+    if start_index < 0 || start_index > end_index {
+        return Err(ShellError::UnsupportedInput(
+            String::from(
+                "start index can't be negative or greater than end index. Invalid start index",
+            ),
+            head,
+        ));
+    }
+
+    if end_index < 0 || end_index < start_index || end_index > input_len as i32 {
+        return Err(ShellError::UnsupportedInput(
+            String::from(
+            "end index can't be negative, smaller than start index or greater than input length. Invalid end index"),
+            head,
+        ));
+    }
+    Ok(IndexOfOptionalBounds(start_index, end_index))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use super::{action, Arguments, SubCommand};
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+
+    #[test]
+    fn returns_index_of_substring() {
+        let word = Value::String {
+            val: String::from("Cargo.tomL"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from(".tomL"),
+
+            range: Some(Value::String {
+                val: String::from(""),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+
+        assert_eq!(actual, Value::test_int(5));
+    }
+    #[test]
+    fn index_of_does_not_exist_in_string() {
+        let word = Value::String {
+            val: String::from("Cargo.tomL"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from("Lm"),
+
+            range: Some(Value::String {
+                val: String::from(""),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+
+        assert_eq!(actual, Value::test_int(-1));
+    }
+
+    #[test]
+    fn returns_index_of_next_substring() {
+        let word = Value::String {
+            val: String::from("Cargo.Cargo"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from("Cargo"),
+
+            range: Some(Value::String {
+                val: String::from("1"),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+        assert_eq!(actual, Value::test_int(6));
+    }
+
+    #[test]
+    fn index_does_not_exist_due_to_end_index() {
+        let word = Value::String {
+            val: String::from("Cargo.Banana"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from("Banana"),
+
+            range: Some(Value::String {
+                val: String::from(",5"),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+        assert_eq!(actual, Value::test_int(-1));
+    }
+
+    #[test]
+    fn returns_index_of_nums_in_middle_due_to_index_limit_from_both_ends() {
+        let word = Value::String {
+            val: String::from("123123123"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from("123"),
+
+            range: Some(Value::String {
+                val: String::from("2,6"),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+        assert_eq!(actual, Value::test_int(3));
+    }
+
+    #[test]
+    fn index_does_not_exists_due_to_strict_bounds() {
+        let word = Value::String {
+            val: String::from("123456"),
+            span: Span::unknown(),
+        };
+
+        let options = Arguments {
+            pattern: String::from("1"),
+
+            range: Some(Value::String {
+                val: String::from("2,4"),
+                span: Span::unknown(),
+            }),
+            column_paths: vec![],
+            end: false,
+        };
+
+        let actual = action(&word, &options, Span::unknown());
+        assert_eq!(actual, Value::test_int(-1));
+    }
+}
diff --git a/crates/nu-command/src/strings/str_/mod.rs b/crates/nu-command/src/strings/str_/mod.rs
index d6ea4d161c..ca656a18d4 100644
--- a/crates/nu-command/src/strings/str_/mod.rs
+++ b/crates/nu-command/src/strings/str_/mod.rs
@@ -5,6 +5,7 @@ mod contains;
 mod downcase;
 mod ends_with;
 mod find_replace;
+mod index_of;
 
 pub use capitalize::SubCommand as StrCapitalize;
 pub use case::*;
@@ -13,3 +14,4 @@ pub use contains::SubCommand as StrContains;
 pub use downcase::SubCommand as StrDowncase;
 pub use ends_with::SubCommand as StrEndswith;
 pub use find_replace::SubCommand as StrFindReplace;
+pub use index_of::SubCommand as StrIndexOf;