Add support for case-sensitive queries

Add _ZO_CASE_SENSITIVITY env var to control whether queries should be
performed in a case-sensitive manner, keeping the current behavior
(case-insensitive) as the default.

Setting _ZO_CASE_SENSITIVITY=case-sensitive changes the query behavior
to be case-sensitive.

CHANGELOG.md

@@ -7,6 +7,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- `$_ZO_CASE_SENSITIVITY` to support case-sensitive querying in addition to the
+  default case-insensitive querying.
+
 ## [0.9.8] - 2025-05-27
 
 ### Added

README.md

@@ -426,6 +426,9 @@ When calling `zoxide init`, the following flags are available:
 Environment variables[^2] can be used for configuration. They must be set before
 `zoxide init` is called.
 
+- `_ZO_CASE_SENSITIVITY`
+  - Defaults to case-insensitive searches. Set to `case-sensitive` for
+    case-sensitive searching.
 - `_ZO_DATA_DIR`
   - Specifies the directory in which the database is stored.
   - The default value varies across OSes:

src/cmd/cmd.rs

@@ -22,6 +22,7 @@ https://github.com/ajeetdsouza/zoxide
 {all-args}{after-help}
 
 <bold><underline>Environment variables:</underline></bold>
+{tab}<bold>_ZO_CASE_SENSITIVITY</bold>{tab}Set case-sensitivity: case-sensitive or case-insensitive (default)
 {tab}<bold>_ZO_DATA_DIR</bold>        {tab}Path for zoxide data files
 {tab}<bold>_ZO_ECHO</bold>            {tab}Print the matched directory before navigating to it when set to 1
 {tab}<bold>_ZO_EXCLUDE_DIRS</bold>    {tab}List of directory globs to be excluded

src/cmd/query.rs

@@ -79,6 +79,7 @@ impl Query {
     fn get_stream<'a>(&self, db: &'a mut Database, now: Epoch) -> Result<Stream<'a>> {
         let mut options = StreamOptions::new(now)
             .with_keywords(self.keywords.iter().map(|s| s.as_str()))
+            .with_case_sensitivity(config::case_sensitivity())
             .with_exclude(config::exclude_dirs()?);
         if !self.all {
             let resolve_symlinks = config::resolve_symlinks();

src/config.rs

@@ -6,6 +6,33 @@ use anyhow::{Context, Result, ensure};
 use glob::Pattern;
 
 use crate::db::Rank;
+use crate::util;
+
+pub enum CaseSensitivity {
+    CaseInsensitive,
+    CaseSensitive,
+}
+
+impl CaseSensitivity {
+    pub fn convert_case(&self, s: &str) -> String {
+        match self {
+            CaseSensitivity::CaseInsensitive => util::to_lowercase(s),
+            CaseSensitivity::CaseSensitive => s.into(),
+        }
+    }
+}
+
+pub fn case_sensitivity() -> CaseSensitivity {
+    env::var_os("_ZO_CASE_SENSITIVITY")
+        .map_or(CaseSensitivity::CaseInsensitive, map_case_sensitivity)
+}
+
+fn map_case_sensitivity(s: OsString) -> CaseSensitivity {
+    match s.to_str() {
+        Some("case-sensitive") => CaseSensitivity::CaseSensitive,
+        _ => CaseSensitivity::CaseInsensitive,
+    }
+}
 
 pub fn data_dir() -> Result<PathBuf> {
     let dir = match env::var_os("_ZO_DATA_DIR") {

src/db/stream.rs

@@ -4,8 +4,9 @@ use std::{fs, path};
 
 use glob::Pattern;
 
+use crate::config::CaseSensitivity;
 use crate::db::{Database, Dir, Epoch};
-use crate::util::{self, MONTH};
+use crate::util::MONTH;
 
 pub struct Stream<'a> {
     db: &'a mut Database,
@@ -48,13 +49,18 @@ impl<'a> Stream<'a> {
     }
 
     fn filter_by_keywords(&self, path: &str) -> bool {
-        let (keywords_last, keywords) = match self.options.keywords.split_last() {
+        let keywords: Vec<String> = self
+            .options
+            .keywords
+            .iter()
+            .map(|s| self.options.case_sensitivity.convert_case(s))
+            .collect();
+
+        let (keywords_last, keywords) = match keywords.split_last() {
             Some(split) => split,
             None => return true,
         };
-
-        let path = util::to_lowercase(path);
-        let mut path = path.as_str();
+        let mut path = &self.options.case_sensitivity.convert_case(path)[..];
         match path.rfind(keywords_last) {
             Some(idx) => {
                 if path[idx + keywords_last.len()..].contains(path::is_separator) {
@@ -112,6 +118,9 @@ pub struct StreamOptions {
     /// Directories that do not exist and haven't been accessed since TTL will
     /// be lazily removed.
     ttl: Epoch,
+
+    /// Whether searching should be perform case sensitively.
+    case_sensitivity: CaseSensitivity,
 }
 
 impl StreamOptions {
@@ -123,6 +132,7 @@ impl StreamOptions {
             exists: false,
             resolve_symlinks: false,
             ttl: now.saturating_sub(3 * MONTH),
+            case_sensitivity: CaseSensitivity::CaseInsensitive,
         }
     }
 
@@ -131,7 +141,12 @@ impl StreamOptions {
         I: IntoIterator,
         I::Item: AsRef<str>,
     {
-        self.keywords = keywords.into_iter().map(util::to_lowercase).collect();
+        self.keywords = keywords.into_iter().map(|s| s.as_ref().into()).collect();
+        self
+    }
+
+    pub fn with_case_sensitivity(mut self, case_sensitivity: CaseSensitivity) -> Self {
+        self.case_sensitivity = case_sensitivity;
         self
     }
 
@@ -185,4 +200,16 @@ mod tests {
         let stream = Stream::new(db, options);
         assert_eq!(is_match, stream.filter_by_keywords(path));
     }
+
+    #[rstest]
+    // Case normalization
+    #[case(&["fOo", "bAr"], "/foo/bar", false)]
+    fn query_case_sensitive(#[case] keywords: &[&str], #[case] path: &str, #[case] is_match: bool) {
+        let db = &mut Database::new(PathBuf::new(), Vec::new(), |_| Vec::new(), false);
+        let options = StreamOptions::new(0)
+            .with_keywords(keywords.iter())
+            .with_case_sensitivity(CaseSensitivity::CaseSensitive);
+        let stream = Stream::new(db, options);
+        assert_eq!(is_match, stream.filter_by_keywords(path));
+    }
 }