feat: support Dust tree by age

completions/_dust

@@ -44,6 +44,8 @@ _dust() {
 '-y+[just like -mtime, but based on file change time]: : ' \
 '--ctime=[just like -mtime, but based on file change time]: : ' \
 '--files0-from=[run dust on NUL-terminated file names specified in file; if argument is -, then read names from standard input]: :_files' \
+'-m+[Directory '\''size'\'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time]: :(a c m)' \
+'--filetime=[Directory '\''size'\'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time]: :(a c m)' \
 '-p[Subdirectories will not have their path shortened]' \
 '--full-paths[Subdirectories will not have their path shortened]' \
 '-L[dereference sym links - Treat sym links as directories and go into them]' \

completions/_dust.ps1

@@ -50,6 +50,8 @@ Register-ArgumentCompleter -Native -CommandName 'dust' -ScriptBlock {
             [CompletionResult]::new('-y', 'y', [CompletionResultType]::ParameterName, 'just like -mtime, but based on file change time')
             [CompletionResult]::new('--ctime', 'ctime', [CompletionResultType]::ParameterName, 'just like -mtime, but based on file change time')
             [CompletionResult]::new('--files0-from', 'files0-from', [CompletionResultType]::ParameterName, 'run dust on NUL-terminated file names specified in file; if argument is -, then read names from standard input')
+            [CompletionResult]::new('-m', 'm', [CompletionResultType]::ParameterName, 'Directory ''size'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time')
+            [CompletionResult]::new('--filetime', 'filetime', [CompletionResultType]::ParameterName, 'Directory ''size'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time')
             [CompletionResult]::new('-p', 'p', [CompletionResultType]::ParameterName, 'Subdirectories will not have their path shortened')
             [CompletionResult]::new('--full-paths', 'full-paths', [CompletionResultType]::ParameterName, 'Subdirectories will not have their path shortened')
             [CompletionResult]::new('-L', 'L ', [CompletionResultType]::ParameterName, 'dereference sym links - Treat sym links as directories and go into them')

completions/dust.bash

@@ -19,7 +19,7 @@ _dust() {
 
     case "${cmd}" in
         dust)
-            opts="-d -T -n -p -X -I -L -x -s -r -c -C -b -B -z -R -f -i -v -e -t -w -P -D -F -o -S -j -M -A -y -h -V --depth --threads --number-of-lines --full-paths --ignore-directory --ignore-all-in-file --dereference-links --limit-filesystem --apparent-size --reverse --no-colors --force-colors --no-percent-bars --bars-on-right --min-size --screen-reader --skip-total --filecount --ignore_hidden --invert-filter --filter --file_types --terminal_width --no-progress --print-errors --only-dir --only-file --output-format --stack-size --output-json --mtime --atime --ctime --files0-from --help --version [PATH]..."
+            opts="-d -T -n -p -X -I -L -x -s -r -c -C -b -B -z -R -f -i -v -e -t -w -P -D -F -o -S -j -M -A -y -m -h -V --depth --threads --number-of-lines --full-paths --ignore-directory --ignore-all-in-file --dereference-links --limit-filesystem --apparent-size --reverse --no-colors --force-colors --no-percent-bars --bars-on-right --min-size --screen-reader --skip-total --filecount --ignore_hidden --invert-filter --filter --file_types --terminal_width --no-progress --print-errors --only-dir --only-file --output-format --stack-size --output-json --mtime --atime --ctime --files0-from --filetime --help --version [PATH]..."
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 1 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -163,6 +163,14 @@ _dust() {
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0
                     ;;
+                --filetime)
+                    COMPREPLY=($(compgen -W "a c m" -- "${cur}"))
+                    return 0
+                    ;;
+                -m)
+                    COMPREPLY=($(compgen -W "a c m" -- "${cur}"))
+                    return 0
+                    ;;
                 *)
                     COMPREPLY=()
                     ;;

completions/dust.elv

@@ -47,6 +47,8 @@ set edit:completion:arg-completer[dust] = {|@words|
             cand -y 'just like -mtime, but based on file change time'
             cand --ctime 'just like -mtime, but based on file change time'
             cand --files0-from 'run dust on NUL-terminated file names specified in file; if argument is -, then read names from standard input'
+            cand -m 'Directory ''size'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time'
+            cand --filetime 'Directory ''size'' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time'
             cand -p 'Subdirectories will not have their path shortened'
             cand --full-paths 'Subdirectories will not have their path shortened'
             cand -L 'dereference sym links - Treat sym links as directories and go into them'

completions/dust.fish

@@ -13,6 +13,7 @@ complete -c dust -s M -l mtime -d '+/-n matches files modified more/less than n
 complete -c dust -s A -l atime -d 'just like -mtime, but based on file access time' -r
 complete -c dust -s y -l ctime -d 'just like -mtime, but based on file change time' -r
 complete -c dust -l files0-from -d 'run dust on NUL-terminated file names specified in file; if argument is -, then read names from standard input' -r -F
+complete -c dust -s m -l filetime -d 'Directory \'size\' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time' -r -f -a "{a	'',c	'',m	''}"
 complete -c dust -s p -l full-paths -d 'Subdirectories will not have their path shortened'
 complete -c dust -s L -l dereference-links -d 'dereference sym links - Treat sym links as directories and go into them'
 complete -c dust -s x -l limit-filesystem -d 'Only count the files and directories on the same filesystem as the supplied directory'

man-page/dust.1

@@ -4,7 +4,7 @@
 .SH NAME
 Dust \- Like du but more intuitive
 .SH SYNOPSIS
-\fBdust\fR [\fB\-d\fR|\fB\-\-depth\fR] [\fB\-T\fR|\fB\-\-threads\fR] [\fB\-n\fR|\fB\-\-number\-of\-lines\fR] [\fB\-p\fR|\fB\-\-full\-paths\fR] [\fB\-X\fR|\fB\-\-ignore\-directory\fR] [\fB\-I\fR|\fB\-\-ignore\-all\-in\-file\fR] [\fB\-L\fR|\fB\-\-dereference\-links\fR] [\fB\-x\fR|\fB\-\-limit\-filesystem\fR] [\fB\-s\fR|\fB\-\-apparent\-size\fR] [\fB\-r\fR|\fB\-\-reverse\fR] [\fB\-c\fR|\fB\-\-no\-colors\fR] [\fB\-C\fR|\fB\-\-force\-colors\fR] [\fB\-b\fR|\fB\-\-no\-percent\-bars\fR] [\fB\-B\fR|\fB\-\-bars\-on\-right\fR] [\fB\-z\fR|\fB\-\-min\-size\fR] [\fB\-R\fR|\fB\-\-screen\-reader\fR] [\fB\-\-skip\-total\fR] [\fB\-f\fR|\fB\-\-filecount\fR] [\fB\-i\fR|\fB\-\-ignore_hidden\fR] [\fB\-v\fR|\fB\-\-invert\-filter\fR] [\fB\-e\fR|\fB\-\-filter\fR] [\fB\-t\fR|\fB\-\-file_types\fR] [\fB\-w\fR|\fB\-\-terminal_width\fR] [\fB\-P\fR|\fB\-\-no\-progress\fR] [\fB\-\-print\-errors\fR] [\fB\-D\fR|\fB\-\-only\-dir\fR] [\fB\-F\fR|\fB\-\-only\-file\fR] [\fB\-o\fR|\fB\-\-output\-format\fR] [\fB\-S\fR|\fB\-\-stack\-size\fR] [\fB\-j\fR|\fB\-\-output\-json\fR] [\fB\-M\fR|\fB\-\-mtime\fR] [\fB\-A\fR|\fB\-\-atime\fR] [\fB\-y\fR|\fB\-\-ctime\fR] [\fB\-\-files0\-from\fR] [\fB\-h\fR|\fB\-\-help\fR] [\fB\-V\fR|\fB\-\-version\fR] [\fIPATH\fR] 
+\fBdust\fR [\fB\-d\fR|\fB\-\-depth\fR] [\fB\-T\fR|\fB\-\-threads\fR] [\fB\-n\fR|\fB\-\-number\-of\-lines\fR] [\fB\-p\fR|\fB\-\-full\-paths\fR] [\fB\-X\fR|\fB\-\-ignore\-directory\fR] [\fB\-I\fR|\fB\-\-ignore\-all\-in\-file\fR] [\fB\-L\fR|\fB\-\-dereference\-links\fR] [\fB\-x\fR|\fB\-\-limit\-filesystem\fR] [\fB\-s\fR|\fB\-\-apparent\-size\fR] [\fB\-r\fR|\fB\-\-reverse\fR] [\fB\-c\fR|\fB\-\-no\-colors\fR] [\fB\-C\fR|\fB\-\-force\-colors\fR] [\fB\-b\fR|\fB\-\-no\-percent\-bars\fR] [\fB\-B\fR|\fB\-\-bars\-on\-right\fR] [\fB\-z\fR|\fB\-\-min\-size\fR] [\fB\-R\fR|\fB\-\-screen\-reader\fR] [\fB\-\-skip\-total\fR] [\fB\-f\fR|\fB\-\-filecount\fR] [\fB\-i\fR|\fB\-\-ignore_hidden\fR] [\fB\-v\fR|\fB\-\-invert\-filter\fR] [\fB\-e\fR|\fB\-\-filter\fR] [\fB\-t\fR|\fB\-\-file_types\fR] [\fB\-w\fR|\fB\-\-terminal_width\fR] [\fB\-P\fR|\fB\-\-no\-progress\fR] [\fB\-\-print\-errors\fR] [\fB\-D\fR|\fB\-\-only\-dir\fR] [\fB\-F\fR|\fB\-\-only\-file\fR] [\fB\-o\fR|\fB\-\-output\-format\fR] [\fB\-S\fR|\fB\-\-stack\-size\fR] [\fB\-j\fR|\fB\-\-output\-json\fR] [\fB\-M\fR|\fB\-\-mtime\fR] [\fB\-A\fR|\fB\-\-atime\fR] [\fB\-y\fR|\fB\-\-ctime\fR] [\fB\-\-files0\-from\fR] [\fB\-m\fR|\fB\-\-filetime\fR] [\fB\-h\fR|\fB\-\-help\fR] [\fB\-V\fR|\fB\-\-version\fR] [\fIPATH\fR] 
 .SH DESCRIPTION
 Like du but more intuitive
 .SH OPTIONS
@@ -115,6 +115,13 @@ just like \-mtime, but based on file change time
 \fB\-\-files0\-from\fR
 run dust on NUL\-terminated file names specified in file; if argument is \-, then read names from standard input
 .TP
+\fB\-m\fR, \fB\-\-filetime\fR
+Directory \*(Aqsize\*(Aq is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time
+.br
+
+.br
+[\fIpossible values: \fRa, c, m]
+.TP
 \fB\-h\fR, \fB\-\-help\fR
 Print help
 .TP

src/cli.rs

@@ -294,4 +294,16 @@ pub fn build_cli() -> Command {
                 .num_args(1)
                 .help("run dust on NUL-terminated file names specified in file; if argument is -, then read names from standard input"),
         )
+        .arg(
+            Arg::new("filetime")
+                .short('m')
+                .long("filetime")
+                .num_args(1)
+                .value_parser([
+                    PossibleValue::new("a").alias("accessed"),
+                    PossibleValue::new("c").alias("changed"),
+                    PossibleValue::new("m").alias("modified"),
+                ])
+                .help("Directory 'size' is max filetime of child files instead of disk size. while a/c/m for last accessed/changed/modified time"),
+        )
 }

src/config.rs

@@ -1,3 +1,4 @@
+use crate::node::FileTime;
 use chrono::{Local, TimeZone};
 use clap::ArgMatches;
 use config_file::FromConfigFile;
@@ -84,6 +85,20 @@ impl Config {
         })
         .to_lowercase()
     }
+
+    pub fn get_filetime(&self, options: &ArgMatches) -> Option<FileTime> {
+        let out_fmt = options.get_one::<String>("filetime");
+        match out_fmt {
+            None => None,
+            Some(x) => match x.as_str() {
+                "m" | "modified" => Some(FileTime::Modified),
+                "a" | "accessed" => Some(FileTime::Accessed),
+                "c" | "changed" => Some(FileTime::Changed),
+                _ => unreachable!(),
+            },
+        }
+    }
+
     pub fn get_skip_total(&self, options: &ArgMatches) -> bool {
         Some(true) == self.skip_total || options.get_flag("skip_total")
     }
@@ -159,7 +174,7 @@ impl Config {
         )
     }
 
-    pub fn get_created_time_operator(&self, options: &ArgMatches) -> Option<(Operater, i64)> {
+    pub fn get_changed_time_operator(&self, options: &ArgMatches) -> Option<(Operater, i64)> {
         get_filter_time_operator(
             options.get_one::<String>("ctime"),
             get_current_date_epoch_seconds(),
@@ -259,6 +274,7 @@ mod tests {
     #[allow(unused_imports)]
     use super::*;
     use chrono::{Datelike, Timelike};
+    use clap::builder::PossibleValue;
     use clap::{value_parser, Arg, ArgMatches, Command};
 
     #[test]
@@ -338,4 +354,56 @@ mod tests {
             )
             .get_matches_from(args)
     }
+
+    #[test]
+    fn test_get_filetime() {
+        // No config and no flag.
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust"]);
+        assert_eq!(c.get_filetime(&args), None);
+
+        // Config is not defined and flag is defined as access time
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "a"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Accessed));
+
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "accessed"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Accessed));
+
+        // Config is not defined and flag is defined as modified time
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "m"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Modified));
+
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "modified"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Modified));
+
+        // Config is not defined and flag is defined as changed time
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "c"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Changed));
+
+        let c = Config::default();
+        let args = get_filetime_args(vec!["dust", "--filetime", "changed"]);
+        assert_eq!(c.get_filetime(&args), Some(FileTime::Changed));
+    }
+
+    fn get_filetime_args(args: Vec<&str>) -> ArgMatches {
+        Command::new("Dust")
+        .arg(
+            Arg::new("filetime")
+                .short('m')
+                .long("filetime")
+                .num_args(1)
+                .value_parser([
+                    PossibleValue::new("a").alias("accessed"),
+                    PossibleValue::new("c").alias("changed"),
+                    PossibleValue::new("m").alias("modified"),
+                ])
+                .help("Directory 'size' is max filetime of child files instead of disk size. while a/c/m for accessed/changed/modified time"),
+        )
+            .get_matches_from(args)
+    }
 }

src/dir_walker.rs

@@ -21,6 +21,7 @@ use std::collections::HashSet;
 use crate::node::build_node;
 use std::fs::DirEntry;
 
+use crate::node::FileTime;
 use crate::platform::get_metadata;
 
 #[derive(Debug)]
@@ -40,6 +41,7 @@ pub struct WalkData<'a> {
     pub filter_changed_time: Option<(Operater, i64)>,
     pub use_apparent_size: bool,
     pub by_filecount: bool,
+    pub by_filetime: &'a Option<FileTime>,
     pub ignore_hidden: bool,
     pub follow_links: bool,
     pub progress_data: Arc<PAtomicInfo>,
@@ -57,19 +59,15 @@ pub fn walk_it(dirs: HashSet<PathBuf>, walk_data: &WalkData) -> Vec<Node> {
 
             prog_data.state.store(Operation::PREPARING, ORDERING);
 
-            clean_inodes(node, &mut inodes, walk_data.use_apparent_size)
+            clean_inodes(node, &mut inodes, walk_data)
         })
         .collect();
     top_level_nodes
 }
 
 // Remove files which have the same inode, we don't want to double count them.
-fn clean_inodes(
+fn clean_inodes(x: Node, inodes: &mut HashSet<(u64, u64)>, walk_data: &WalkData) -> Option<Node> {
-    x: Node,
+    if !walk_data.use_apparent_size {
-    inodes: &mut HashSet<(u64, u64)>,
-    use_apparent_size: bool,
-) -> Option<Node> {
-    if !use_apparent_size {
         if let Some(id) = x.inode_device {
             if !inodes.insert(id) {
                 return None;
@@ -82,12 +80,25 @@ fn clean_inodes(
     tmp.sort_by(sort_by_inode);
     let new_children: Vec<_> = tmp
         .into_iter()
-        .filter_map(|c| clean_inodes(c, inodes, use_apparent_size))
+        .filter_map(|c| clean_inodes(c, inodes, walk_data))
         .collect();
 
+    let actual_size = if walk_data.by_filetime.is_some() {
+        // If by_filetime is Some, directory 'size' is the maximum filetime among child files instead of disk size
+        new_children
+            .iter()
+            .map(|c| c.size)
+            .chain(std::iter::once(x.size))
+            .max()
+            .unwrap_or(0)
+    } else {
+        // If by_filetime is None, directory 'size' is the sum of disk sizes or file counts of child files
+        x.size + new_children.iter().map(|c| c.size).sum::<u64>()
+    };
+
     Some(Node {
         name: x.name,
-        size: x.size + new_children.iter().map(|c| c.size).sum::<u64>(),
+        size: actual_size,
         children: new_children,
         inode_device: x.inode_device,
         depth: x.depth,
@@ -280,17 +291,43 @@ mod tests {
         }
     }
 
+    #[cfg(test)]
+    fn create_walker<'a>(use_apparent_size: bool) -> WalkData<'a> {
+        use crate::PIndicator;
+        let indicator = PIndicator::build_me();
+        WalkData {
+            ignore_directories: HashSet::new(),
+            filter_regex: &[],
+            invert_filter_regex: &[],
+            allowed_filesystems: HashSet::new(),
+            filter_modified_time: Some((Operater::GreaterThan, 0)),
+            filter_accessed_time: Some((Operater::GreaterThan, 0)),
+            filter_changed_time: Some((Operater::GreaterThan, 0)),
+            use_apparent_size,
+            by_filecount: false,
+            by_filetime: &None,
+            ignore_hidden: false,
+            follow_links: false,
+            progress_data: indicator.data.clone(),
+            errors: Arc::new(Mutex::new(RuntimeErrors::default())),
+        }
+    }
+
     #[test]
     #[allow(clippy::redundant_clone)]
     fn test_should_ignore_file() {
         let mut inodes = HashSet::new();
         let n = create_node();
+        let walkdata = create_walker(false);
 
         // First time we insert the node
-        assert_eq!(clean_inodes(n.clone(), &mut inodes, false), Some(n.clone()));
+        assert_eq!(
+            clean_inodes(n.clone(), &mut inodes, &walkdata),
+            Some(n.clone())
+        );
 
         // Second time is a duplicate - we ignore it
-        assert_eq!(clean_inodes(n.clone(), &mut inodes, false), None);
+        assert_eq!(clean_inodes(n.clone(), &mut inodes, &walkdata), None);
     }
 
     #[test]
@@ -298,10 +335,17 @@ mod tests {
     fn test_should_not_ignore_files_if_using_apparent_size() {
         let mut inodes = HashSet::new();
         let n = create_node();
+        let walkdata = create_walker(true);
 
         // If using apparent size we include Nodes, even if duplicate inodes
-        assert_eq!(clean_inodes(n.clone(), &mut inodes, true), Some(n.clone()));
+        assert_eq!(
-        assert_eq!(clean_inodes(n.clone(), &mut inodes, true), Some(n.clone()));
+            clean_inodes(n.clone(), &mut inodes, &walkdata),
+            Some(n.clone())
+        );
+        assert_eq!(
+            clean_inodes(n.clone(), &mut inodes, &walkdata),
+            Some(n.clone())
+        );
     }
 
     #[test]

src/display.rs

@@ -1,4 +1,5 @@
 use crate::display_node::DisplayNode;
+use crate::node::FileTime;
 
 use ansi_term::Colour::Red;
 use lscolors::{LsColors, Style};
@@ -7,6 +8,7 @@ use unicode_width::UnicodeWidthStr;
 
 use stfu8::encode_u8;
 
+use chrono::{DateTime, Local, TimeZone, Utc};
 use std::cmp::max;
 use std::cmp::min;
 use std::fs;
@@ -16,12 +18,14 @@ use thousands::Separable;
 
 pub static UNITS: [char; 4] = ['T', 'G', 'M', 'K'];
 static BLOCKS: [char; 5] = ['█', '▓', '▒', '░', ' '];
+const FILETIME_SHOW_LENGTH: usize = 19;
 
 pub struct InitialDisplayData {
     pub short_paths: bool,
     pub is_reversed: bool,
     pub colors_on: bool,
     pub by_filecount: bool,
+    pub by_filetime: Option<FileTime>,
     pub is_screen_reader: bool,
     pub output_format: String,
     pub bars_on_right: bool,
@@ -141,6 +145,8 @@ pub fn draw_it(
     let num_chars_needed_on_left_most = if idd.by_filecount {
         let max_size = biggest.size;
         max_size.separate_with_commas().chars().count()
+    } else if idd.by_filetime.is_some() {
+        FILETIME_SHOW_LENGTH
     } else {
         find_biggest_size_str(root_node, &idd.output_format)
     };
@@ -342,6 +348,8 @@ pub fn format_string(
     if display_data.initial.is_screen_reader {
         // if screen_reader then bars is 'depth'
         format!("{pretty_name} {bars} {pretty_size}{percent}")
+    } else if display_data.initial.by_filetime.is_some() {
+        format!("{pretty_size} {indent}{pretty_name}")
     } else {
         format!("{pretty_size} {indent} {pretty_name}{percent}")
     }
@@ -376,6 +384,8 @@ fn get_name_percent(
 fn get_pretty_size(node: &DisplayNode, is_biggest: bool, display_data: &DisplayData) -> String {
     let output = if display_data.initial.by_filecount {
         node.size.separate_with_commas()
+    } else if display_data.initial.by_filetime.is_some() {
+        get_pretty_file_modified_time(node.size as i64)
     } else {
         human_readable_number(node.size, &display_data.initial.output_format)
     };
@@ -389,6 +399,14 @@ fn get_pretty_size(node: &DisplayNode, is_biggest: bool, display_data: &DisplayD
     }
 }
 
+fn get_pretty_file_modified_time(timestamp: i64) -> String {
+    let datetime: DateTime<Utc> = Utc.timestamp_opt(timestamp, 0).unwrap();
+
+    let local_datetime = datetime.with_timezone(&Local);
+
+    local_datetime.format("%Y-%m-%dT%H:%M:%S").to_string()
+}
+
 fn get_pretty_name(
     node: &DisplayNode,
     name_and_padding: String,
@@ -469,6 +487,7 @@ mod tests {
             is_reversed: false,
             colors_on: false,
             by_filecount: false,
+            by_filetime: None,
             is_screen_reader: false,
             output_format: "".into(),
             bars_on_right: false,
@@ -625,4 +644,37 @@ mod tests {
         let bar = dd.generate_bar(&n, 5);
         assert_eq!(bar, "████▓▓▓▓▓▓▓▓▓");
     }
+
+    #[test]
+    fn test_get_pretty_file_modified_time() {
+        // Create a timestamp for 2023-07-12 00:00:00 in local time
+        let local_dt = Local.with_ymd_and_hms(2023, 7, 12, 0, 0, 0).unwrap();
+        let timestamp = local_dt.timestamp();
+
+        // Format expected output
+        let expected_output = local_dt.format("%Y-%m-%dT%H:%M:%S").to_string();
+
+        assert_eq!(get_pretty_file_modified_time(timestamp), expected_output);
+
+        // Test another timestamp
+        let local_dt = Local.with_ymd_and_hms(2020, 1, 1, 12, 0, 0).unwrap();
+        let timestamp = local_dt.timestamp();
+        let expected_output = local_dt.format("%Y-%m-%dT%H:%M:%S").to_string();
+
+        assert_eq!(get_pretty_file_modified_time(timestamp), expected_output);
+
+        // Test timestamp for epoch start (1970-01-01T00:00:00)
+        let local_dt = Local.with_ymd_and_hms(1970, 1, 1, 0, 0, 0).unwrap();
+        let timestamp = local_dt.timestamp();
+        let expected_output = local_dt.format("%Y-%m-%dT%H:%M:%S").to_string();
+
+        assert_eq!(get_pretty_file_modified_time(timestamp), expected_output);
+
+        // Test a future timestamp
+        let local_dt = Local.with_ymd_and_hms(2030, 12, 25, 6, 30, 0).unwrap();
+        let timestamp = local_dt.timestamp();
+        let expected_output = local_dt.format("%Y-%m-%dT%H:%M:%S").to_string();
+
+        assert_eq!(get_pretty_file_modified_time(timestamp), expected_output);
+    }
 }

src/filter.rs

@@ -1,4 +1,5 @@
 use crate::display_node::DisplayNode;
+use crate::node::FileTime;
 use crate::node::Node;
 use std::collections::BinaryHeap;
 use std::collections::HashMap;
@@ -14,7 +15,11 @@ pub struct AggregateData {
     pub using_a_filter: bool,
 }
 
-pub fn get_biggest(top_level_nodes: Vec<Node>, display_data: AggregateData) -> Option<DisplayNode> {
+pub fn get_biggest(
+    top_level_nodes: Vec<Node>,
+    display_data: AggregateData,
+    by_filetime: &Option<FileTime>,
+) -> Option<DisplayNode> {
     if top_level_nodes.is_empty() {
         // perhaps change this, bring back Error object?
         return None;
@@ -24,7 +29,15 @@ pub fn get_biggest(top_level_nodes: Vec<Node>, display_data: AggregateData) -> O
     let root;
 
     if number_top_level_nodes > 1 {
-        let size = top_level_nodes.iter().map(|node| node.size).sum();
+        let size = if by_filetime.is_some() {
+            top_level_nodes
+                .iter()
+                .map(|node| node.size)
+                .max()
+                .unwrap_or(0)
+        } else {
+            top_level_nodes.iter().map(|node| node.size).sum()
+        };
         root = Node {
             name: PathBuf::from("(total)"),
             size,

src/filter_type.rs

@@ -1,4 +1,5 @@
 use crate::display_node::DisplayNode;
+use crate::node::FileTime;
 use crate::node::Node;
 use std::collections::HashMap;
 use std::ffi::OsStr;
@@ -10,7 +11,11 @@ struct ExtensionNode<'a> {
     extension: Option<&'a OsStr>,
 }
 
-pub fn get_all_file_types(top_level_nodes: &[Node], n: usize) -> Option<DisplayNode> {
+pub fn get_all_file_types(
+    top_level_nodes: &[Node],
+    n: usize,
+    by_filetime: &Option<FileTime>,
+) -> Option<DisplayNode> {
     let ext_nodes = {
         let mut extension_cumulative_sizes = HashMap::new();
         build_by_all_file_types(top_level_nodes, &mut extension_cumulative_sizes);
@@ -44,16 +49,27 @@ pub fn get_all_file_types(top_level_nodes: &[Node], n: usize) -> Option<DisplayN
 
     // ...then, aggregate the remaining nodes (if any) into a single  "(others)" node
     if ext_nodes_iter.len() > 0 {
+        let actual_size = if by_filetime.is_some() {
+            ext_nodes_iter.map(|node| node.size).max().unwrap_or(0)
+        } else {
+            ext_nodes_iter.map(|node| node.size).sum()
+        };
         displayed.push(DisplayNode {
             name: PathBuf::from("(others)"),
-            size: ext_nodes_iter.map(|node| node.size).sum(),
+            size: actual_size,
             children: vec![],
         });
     }
 
+    let actual_size: u64 = if by_filetime.is_some() {
+        displayed.iter().map(|node| node.size).max().unwrap_or(0)
+    } else {
+        displayed.iter().map(|node| node.size).sum()
+    };
+
     let result = DisplayNode {
         name: PathBuf::from("(total)"),
-        size: displayed.iter().map(|node| node.size).sum(),
+        size: actual_size,
         children: displayed,
     };
 

src/main.rs

@@ -224,6 +224,7 @@ fn main() {
         .collect::<Vec<Regex>>();
 
     let by_filecount = options.get_flag("by_filecount");
+    let by_filetime = config.get_filetime(&options);
     let limit_filesystem = options.get_flag("limit_filesystem");
     let follow_links = options.get_flag("dereference_links");
 
@@ -248,7 +249,7 @@ fn main() {
 
     let filter_modified_time = config.get_modified_time_operator(&options);
     let filter_accessed_time = config.get_accessed_time_operator(&options);
-    let filter_changed_time = config.get_created_time_operator(&options);
+    let filter_changed_time = config.get_changed_time_operator(&options);
 
     let walk_data = WalkData {
         ignore_directories: ignored_full_path,
@@ -260,6 +261,7 @@ fn main() {
         filter_changed_time,
         use_apparent_size: config.get_apparent_size(&options),
         by_filecount,
+        by_filetime: &by_filetime,
         ignore_hidden,
         follow_links,
         progress_data: indicator.data.clone(),
@@ -272,7 +274,7 @@ fn main() {
     let top_level_nodes = walk_it(simplified_dirs, &walk_data);
 
     let tree = match summarize_file_types {
-        true => get_all_file_types(&top_level_nodes, number_of_lines),
+        true => get_all_file_types(&top_level_nodes, number_of_lines, &by_filetime),
         false => {
             let agg_data = AggregateData {
                 min_size: config.get_min_size(&options),
@@ -282,7 +284,7 @@ fn main() {
                 depth,
                 using_a_filter: !filter_regexs.is_empty() || !invert_filter_regexs.is_empty(),
             };
-            get_biggest(top_level_nodes, agg_data)
+            get_biggest(top_level_nodes, agg_data, &by_filetime)
         }
     };
 
@@ -334,6 +336,7 @@ fn main() {
             is_reversed: !config.get_reverse(&options),
             colors_on: is_colors,
             by_filecount,
+            by_filetime,
             is_screen_reader: config.get_screen_reader(&options),
             output_format,
             bars_on_right: config.get_bars_on_right(&options),

src/node.rs

@@ -16,6 +16,13 @@ pub struct Node {
     pub depth: usize,
 }
 
+#[derive(Debug, PartialEq)]
+pub enum FileTime {
+    Modified,
+    Accessed,
+    Changed,
+}
+
 #[allow(clippy::too_many_arguments)]
 pub fn build_node(
     dir: PathBuf,
@@ -27,6 +34,7 @@ pub fn build_node(
 ) -> Option<Node> {
     let use_apparent_size = walk_data.use_apparent_size;
     let by_filecount = walk_data.by_filecount;
+    let by_filetime = &walk_data.by_filetime;
 
     get_metadata(
         &dir,
@@ -51,6 +59,13 @@ pub fn build_node(
             0
         } else if by_filecount {
             1
+        } else if by_filetime.is_some() {
+            match by_filetime {
+                Some(FileTime::Modified) => data.2 .0.unsigned_abs(),
+                Some(FileTime::Accessed) => data.2 .1.unsigned_abs(),
+                Some(FileTime::Changed) => data.2 .2.unsigned_abs(),
+                None => unreachable!(),
+            }
         } else {
             data.0
         };