### Install QDirStat

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Install QDirStat after compiling. This command typically installs to the default /usr directory. Use 'su -c make install' for root privileges if needed.

```bash
sudo make install
```

--------------------------------

### Build and Install Software Manually

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Unpkg-View.md

Standard command sequence for compiling and installing software directly to system directories.

```bash
make && sudo make install
```

--------------------------------

### Install and Run QDirStat from Live Media

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Install QDirStat on a live Linux system using `apt` and then run it with `sudo` to analyze a mounted filesystem. Running with `sudo` ensures access to all subdirectories.

```bash
tux@live-linux:~$ sudo apt install qdirstat
tux@live-linux:~$ xhost +
tux@live-linux:~$ sudo qdirstat /mnt
```

--------------------------------

### Install QDirStat Packages on Ubuntu

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Use this command to install the necessary packages for building QDirStat on Ubuntu. It includes build essentials, Qt6 development files, and zlib.

```bash
sudo apt-get install build-essential qtbase6-dev qt6-5compat-dev zlib1g-dev
```

--------------------------------

### Install QDirStat to Custom Directory

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Install QDirStat to a custom directory by specifying the INSTALL_PREFIX during the qmake6 configuration. This is useful for non-standard installations.

```bash
qmake6 INSTALL_PREFIX=/usr/local
```

--------------------------------

### Install QDirStat Packages on SUSE

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Install the required development packages for building QDirStat on SUSE Linux. This includes C/C++ development tools, Qt6 development files, and zlib.

```bash
sudo zypper install -t pattern devel_C_C++
sudo zypper install qt6-widgets-devel qt6-qt5compat-devel zlib-devel
```

--------------------------------

### Start QDirStat with Package Filter (Starts With)

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Launch QDirStat and filter packages starting with 'chrom'. This uses auto-mode, defaulting to a 'starts with' match for package names. Patterns are case-insensitive.

```bash
qdirstat pkg:/chrom
```

--------------------------------

### QDirStat Cache File Format Example

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/cache-file-format.txt

An example of a QDirStat cache file in version 2.0 format. This format is used for storing directory and file information. Lines starting with '#' are comments and are ignored.

```text
# Generated by qdirstat-cache-writer
# Do not edit!
#
# Type  path                            size     uid   gid  perm.       mtime      <optional fields>

D /work/home/sh/src/qdirstat            4096    1000  1000  0775        0x65e0ce47
```

--------------------------------

### Generate Dpkg File Lists

Source: https://github.com/shundhammer/qdirstat/blob/master/scripts/pkg-tools/README.md

Creates lists of installed packages and their files for dpkg-based systems. Output paths are printed to stdout. The QDirStat temporary directory is created if it doesn't exist.

```bash
[sh @ balrog] ...qdirstat/scripts/pkg-tools % complete-filelist-dpkg
2459 /tmp/qdirstat-sh/pkglist.txt
268507 /tmp/qdirstat-sh/filelist.txt
```

--------------------------------

### Install URI::Escape Perl Module

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Install the URI::Escape Perl module using cpan. Ensure 'make' is installed if the installation fails.

```bash
cpan URI::Escape
```

--------------------------------

### Retrieve Installed Package List

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Commands used by QDirStat to fetch the list of installed packages from the system.

```bash
dpkg-query --show --showformat='${Package} | ${Version} | ${Architecture} | ${Status}\n'
```

```bash
rpm -qa --queryformat '%{name} | %{version}-%{release} | %{arch}\n'
```

```bash
pacman -Qn
```

--------------------------------

### Start QDirStat with Unpackaged Files View

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Unpkg-View.md

Launches QDirStat directly into the unpackaged files view for a specified directory. Uses previously saved exclude and ignore patterns.

```bash
qdirstat unpkg:/usr/share
```

```bash
qdirstat unpkg:/
```

--------------------------------

### Select Qt6 Environment on Ubuntu

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

If you have multiple Qt versions installed, use qtchooser to select Qt6 for building QDirStat. This ensures the correct Qt libraries are used.

```bash
sudo apt-get install qtchooser
export QT_SELECT="qt6"
```

--------------------------------

### Display Disk Usage of Qt Installation Directory

Source: https://github.com/shundhammer/qdirstat/wiki/QDirStat-MacOS-Dev

Use 'du -skh *' to display disk usage for each item in the current directory. This is useful for understanding the space occupied by a Qt installation.

```bash
cd ~/qt
du -skh *

```

--------------------------------

### Start QDirStat with Package Filter (Wildcard)

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Launch QDirStat and filter for packages containing 'gtk'. The '*' wildcards must be quoted to prevent shell expansion. Patterns are case-insensitive.

```bash
qdirstat "pkg:/*gtk*"
```

--------------------------------

### Start QDirStat with Package Filter (Regular Expression)

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Launch QDirStat and filter for packages matching the regular expression '.*qt[45].*'. This selects packages related to Qt4 or Qt5. Patterns are case-insensitive.

```bash
qdirstat "pkg:/.*qt[45].*"
```

--------------------------------

### Profile QDirStat with Valgrind

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Debugging-Tips.md

Start QDirStat with Valgrind's callgrind tool to profile its execution. This significantly slows down the application, so avoid using very large directories. Results are saved to callgrind.out.* files.

```bash
valgrind --tool=callgrind --dump-instr=yes --simulate-cache=yes --collect-jumps=yes qdirstat ~
```

--------------------------------

### Filter Snap Packages with df

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/DevHistory.md

Example command to identify snap package loopback mounts cluttering filesystem output.

```bash
df -hT | grep snap

/dev/loop0  squashfs  159M  159M  0 100% /snap/chromium/1244
/dev/loop1  squashfs   55M   55M  0 100% /snap/core18/1880
/dev/loop2  squashfs   63M   63M  0 100% /snap/gtk-common-themes/1506
/dev/loop3  squashfs   30M   30M  0 100% /snap/snapd/8542
```

--------------------------------

### Start QDirStat Without Directory Prompt

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Unpkg-View.md

Starts QDirStat without prompting for a directory, allowing immediate access to the menu for selecting a scan target.

```bash
qdirstat -d
```

--------------------------------

### Start QDirStat with Package Filter (Multiple Regex)

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Launch QDirStat and filter for packages matching a list of common browser names using a regular expression. Use anchors like '^' and '$' for precise matching if needed, as regex uses partial matching by default. Patterns are case-insensitive.

```bash
qdirstat "pkg:/(firefox|mozilla|chrome|chromium|opera)"
```

--------------------------------

### Start QDirStat with Package Filter (Exact Match)

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Launch QDirStat and filter for the exact package name 'emacs'. The '=' prefix explicitly sets the match mode to 'exact match'. Patterns are case-insensitive.

```bash
qdirstat pkg:/=emacs
```

--------------------------------

### Create and Checkout a Feature Branch

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/GitHub-Workflow.md

Start by checking out the master branch, then create and switch to a new feature branch for your work. This isolates your changes and makes managing pull requests easier.

```git
git checkout master
git branch kilroy-transmogrify
git checkout kilroy-transmogrify
```

--------------------------------

### Collect Disk Usage Data on Server

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Use qdirstat-cache-writer with root permissions to collect disk usage data for specified filesystems. The first argument is the scan start point, and the last is the output cache file name.

```bash
sudo qdirstat-cache-writer /    myserver-root.cache.gz
sudo qdirstat-cache-writer /var myserver-var.cache.gz
sudo qdirstat-cache-writer /srv myserver-srv.cache.gz
```

--------------------------------

### Create New Feature Branch

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/GitHub-Workflow.md

Starts a new development branch based on the current state of the pull request branch.

```bash
git branch kilroy-hyperforble
git checkout kilroy-hyperforble
...(work in that branch...)
```

--------------------------------

### C++ Brace Style Example

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Contributing.md

Follow this brace style for C++ code, with opening braces on new lines and spaces after opening and before closing parentheses. Avoid K&R style.

```cpp
if ( someCondition )
{
    doSomething( arg1, arg2 )
}
```

--------------------------------

### Configure Qt Environment Variables for MacOS

Source: https://github.com/shundhammer/qdirstat/wiki/QDirStat-MacOS-Dev

Set environment variables to point to your Qt installation directory and its binary path. This allows the system to find Qt tools. Remember to source your shell configuration file after making changes.

```bash
export QT_HOME=$HOME/qt/
export QT_5_15_BIN=$QT_HOME/5.15.0/clang_64/bin
export PATH=$PATH:$QT_5_15_BIN
```

--------------------------------

### Rename Git Remote

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/GitHub-Workflow.md

Rename an existing Git remote, for example, changing 'origin' to 'mine'. This is useful if the default remote name was not set as desired during cloning.

```bash
git remote rename origin mine
```

--------------------------------

### Clear Linux Disk Caches

Source: https://github.com/shundhammer/qdirstat/wiki/disk-usage-tools-compared

Use this command in a root shell to clear the kernel directory caches before performance testing. This ensures consistent results by starting with a cold cache.

```bash
echo 3 >/proc/sys/vm/drop_caches
```

--------------------------------

### Check Disk Usage of a Mounted Directory

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

After mounting a filesystem, use `du -hs` to get a human-readable summary of the disk space used by a specific directory. This helps in identifying large directories that might contain shadowed files.

```bash
tux@live-linux:~$ sudo du -hs /mnt/home
2.0G    /mnt/home
```

--------------------------------

### Display QDirStat Help

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

View all available command-line options for QDirStat by using the --help option.

```bash
qdirstat --help
```

--------------------------------

### Bind-Mount Multiple Directories

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Demonstrates creating target directories and performing bind-mounts for multiple distinct directories, ensuring unique target paths to avoid shadowing.

```bash
root@linux:~# mkdir -p /mnt/shadowed/win_app
root@linux:~# mount -o bind /mnt/root/win/app /mnt/shadowed/win_app
root@linux:~# mkdir -p /mnt/shadowed/win_boot
root@linux:~# mount -o bind /mnt/root/win/app /mnt/shadowed/win_boot
```

--------------------------------

### Build QDirStat on MacOS

Source: https://github.com/shundhammer/qdirstat/wiki/QDirStat-MacOS-Dev

Follow these steps to clone the QDirStat repository, configure the build with qmake, and compile the application using make. The resulting executable will be in a .app directory.

```bash
mkdir ~/work
cd ~/work
git clone https://github.com/shundhammer/qdirstat.git
cd qdirstat
qmake
make
```

--------------------------------

### Launch QDirStat via Command Line

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Use these commands to launch the QDirStat application with specific directories, cache files, or specialized views.

```bash
# Basic usage - scan a directory
qdirstat /home/user/Documents

# Scan with slow update mode (3 sec intervals instead of 333 ms)
qdirstat --slow-update /home/user
qdirstat -s /var/log

# Start without showing the directory selection dialog
qdirstat --dont-ask
qdirstat -d

# Read from a pre-generated cache file
qdirstat --cache /path/to/cache.gz
qdirstat -c /tmp/server-cache.qdirstat.cache.gz

# View installed packages matching a pattern (starts with "chrom")
qdirstat pkg:/chrom

# View all Qt4 or Qt5 packages using regex
qdirstat "pkg:/.*qt[45].*"

# View exact package name only
qdirstat "pkg:/=emacs"

# View unpackaged files in system directories
qdirstat unpkg:/usr/share
qdirstat unpkg:/

# Show help
qdirstat --help
```

--------------------------------

### List All Block Devices with lsblk

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Use `lsblk` to display all block devices and their partitions, regardless of whether they are mounted. This command does not require root permissions.

```console
sh@balrog:~$ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 931,5G  0 disk
├─sda1   8:1    0  97,7G  0 part /win/boot
└─sda2   8:2    0 833,9G  0 part /win/app
sdb      8:16   0 931,5G  0 disk
├─sdb1   8:17   0     2G  0 part
├─sdb2   8:18   0    30G  0 part /hd-root-18-04
├─sdb3   8:19   0    30G  0 part /hd-root-14-04
├─sdb4   8:20   0     1K  0 part
└─sdb5   8:21   0 869,5G  0 part /work
sdc      8:32   0 232,9G  0 disk
├─sdc1   8:33   0     2G  0 part [SWAP]
├─sdc2   8:34   0    30G  0 part /
├─sdc3   8:35   0    30G  0 part /ssd-root-20-04
└─sdc4   8:36   0 170,9G  0 part /ssd-work
sr0     11:0    1  1024M  0 rom
```

--------------------------------

### List Block Devices and Mount Filesystem

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Use `lsblk` to identify partitions and `mount` to access a specific partition from a live environment. This is useful for inspecting filesystems that might be inaccessible from the running system.

```bash
tux@live-linux:~$ lsblk /dev/sdb
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdb      8:16   0 931,5G  0 disk
├─sdb1   8:17   0     2G  0 part
├─sdb2   8:18   0    30G  0 part
├─sdb3   8:19   0    30G  0 part
├─sdb4   8:20   0     1K  0 part
└─sdb5   8:21   0 869,5G  0 part
tux@live-linux:~$ sudo mount /dev/sdb2 /mnt
```

--------------------------------

### Compile QDirStat

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Compile QDirStat from source after setting up the build environment. Navigate to the source directory and run qmake6 followed by make.

```bash
qmake6
make
```

--------------------------------

### Download and Make Executable qdirstat-cache-writer

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Download the qdirstat-cache-writer script to the server and make it executable. It's recommended to review the script's content for security.

```bash
ssh root@myserver
cd /usr/local/bin
wget https://github.com/shundhammer/qdirstat/raw/master/scripts/qdirstat-cache-writer
chmod 755 qdirstat-cache-writer
```

--------------------------------

### Open QDirStat Application on MacOS

Source: https://github.com/shundhammer/qdirstat/wiki/QDirStat-MacOS-Dev

After building QDirStat, you can open the application bundle using the 'open' command or by navigating to it in Finder.

```bash
cd qdirstat.app
open qdirstat.app
```

--------------------------------

### Inspect shadowed files with QDirStat

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Launch QDirStat to visually inspect and manage shadowed files.

```console
root@linux:~# qdirstat /mnt/shadowed
```

--------------------------------

### Access Application Settings

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Manage application configuration using QSettings and the Settings class. Use fixFileOwners to correct permissions after sudo operations.

```cpp
#include "Settings.h"
#include <QSettings>

// Access settings (uses QSettings internally)
QSettings settings;

// General settings
settings.beginGroup("MainWindow");
bool showTreemap = settings.value("ShowTreemap", true).toBool();
int treemapHeight = settings.value("TreemapHeight", 300).toInt();
settings.endGroup();

// Directory tree settings
settings.beginGroup("DirectoryTree");
bool crossFilesystems = settings.value("CrossFilesystems", false).toBool();
int slowUpdateMs = settings.value("SlowUpdateMillisec", 3000).toInt();
settings.endGroup();

// Treemap settings
settings.beginGroup("Treemap");
int minTileSize = settings.value("MinTileSize", 3).toInt();
bool squarified = settings.value("Squarify", true).toBool();
settings.endGroup();

// Package view settings
settings.beginGroup("Pkg");
int maxParallel = settings.value("MaxParallelProcesses", 6).toInt();
int minCacheSize = settings.value("MinCachePkgListSize", 200).toInt();
settings.endGroup();

// Cleanup settings are stored per-cleanup in numbered groups:
// [Cleanup_01], [Cleanup_02], etc.

// MIME categories stored in:
// [MimeCategory_01], [MimeCategory_02], etc.

// Exclude rules stored in:
// [ExcludeRule_01], [ExcludeRule_02], etc.

// Fix file ownership after running with sudo
QDirStat::Settings::fixFileOwners();
```

--------------------------------

### Bind-mount the Root Directory

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Create a directory and then use `mount -o bind` to create a read-only bind mount of the root filesystem. This allows access to the original filesystem structure without interference from other mounts.

```bash
root@linux:~# mkdir -p /mnt/root
root@linux:~# mount -o bind / /mnt/root
```

--------------------------------

### Create Target Directory for Bind-Mount

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Creates a parent directory (`/mnt/shadowed/work`) where a filesystem mount will be bind-mounted.

```bash
root@linux:~# mkdir -p /mnt/shadowed/work
```

--------------------------------

### Package Manager Integration Reference

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/DevHistory.md

Reference for implementing support for additional package managers in QDirStat.

```cpp
https://github.com/shundhammer/qdirstat/blob/master/src/PkgManager.cpp#L140
```

--------------------------------

### Force Cache Recreation with show-unpkg-files

Source: https://github.com/shundhammer/qdirstat/blob/master/scripts/pkg-tools/README.md

Use the -f option with show-unpkg-files to force the recreation of the root cache file and file list, even if they already exist.

```bash
./show-unpkg-files -f
```

--------------------------------

### Run Show Unpackaged Files Script

Source: https://github.com/shundhammer/qdirstat/blob/master/scripts/pkg-tools/README.md

Execute the main script to display unpackaged files. Ensure you have sudo permissions. Be cautious when deleting files in the view.

```bash
./show-unpkg-files
```

--------------------------------

### Fetch the Unshadow Mount Points Script

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Download the latest version of the `unshadow-mount-points` script using `wget`. Ensure the script is downloaded to a suitable location, such as a temporary directory.

```bash
tux@linux:~/tmp> wget https://raw.githubusercontent.com/shundhammer/qdirstat/master/scripts/shadowed/unshadow-mount-points
```

--------------------------------

### Pack the test directory

Source: https://github.com/shundhammer/qdirstat/blob/master/test/data/README.md

Creates a compressed tarball of the test directory. Requires sudo to preserve restrictive permissions and the -S flag to handle sparse files correctly.

```bash
sudo tar cjvf test-dir.tar.bz2 -S test
```

--------------------------------

### Display All Mounts with findmnt

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

A plain `findmnt` command displays all mounted filesystems, including kernel pseudo-filesystems. This can be useful for a comprehensive overview but may include 'cruft'.

```console
sh@balrog:~$ findmnt
TARGE                                SOURCE      FSTYPE    OPTIONS
/                                     /dev/sdc2   ext4      rw,relatime,errors=remount-ro,data=order
├─/sys                                sysfs       sysfs     rw,nosuid,nodev,noexec,relatime
│ ├─/sys/kernel/security              securityfs  securityf rw,nosuid,nodev,noexec,relatime
│ ├─/sys/fs/cgroup                    tmpfs       tmpfs     ro,nosuid,nodev,noexec,mode=755
│ │ ├─/sys/fs/cgroup/unified          cgroup      cgroup2   rw,nosuid,nodev,noexec,relatime,nsdelega
│ │ ├─/sys/fs/cgroup/systemd          cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,xattr,na
│ │ ├─/sys/fs/cgroup/blkio            cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,blkio
│ │ ├─/sys/fs/cgroup/hugetlb          cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,hugetlb
│ │ ├─/sys/fs/cgroup/perf_event       cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,perf_eve
│ │ ├─/sys/fs/cgroup/cpu,cpuacct      cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,cpu,cpua
│ │ ├─/sys/fs/cgroup/net_cls,net_prio cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,net_cls,
│ │ ├─/sys/fs/cgroup/cpuset           cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,cpuset
│ │ ├─/sys/fs/cgroup/pids             cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,pids
│ │ ├─/sys/fs/cgroup/rdma             cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,rdma
│ │ ├─/sys/fs/cgroup/memory           cgroup      cgroup    rw,nosuid,nodev,noexec,relatime,memory
```

--------------------------------

### Troubleshoot Cleanup

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Retry command for the cleanup script if previous attempts failed due to busy mounts.

```console
tux@linux:~/tmp> sudo ./unshadow-mount-points -c
```

--------------------------------

### Configure QDirStat Performance

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Configuration settings for parallel processing and caching thresholds in ~/.config/QDirStat/QDirStat.conf.

```ini
[Pkg]
MaxParallelProcesses=6
```

```ini
[Pkg]
MinCachePkgListSize=200
```

--------------------------------

### Show Btrfs Filesystem Information

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Btrfs-Free-Size.md

Use `btrfs filesystem show` with root permissions to display general information about a Btrfs filesystem, including its label, UUID, total devices, and space used. Provide the mount point as an argument.

```bash
sudo btrfs filesystem show /mybtrfs
```

```bash
sudo btrfs fi show /mybtrfs
```

--------------------------------

### Create QDirStat Cache Manually

Source: https://github.com/shundhammer/qdirstat/blob/master/scripts/pkg-tools/README.md

Manually create a QDirStat cache file for the root directory. This command can be run without root permissions, but may generate warnings and miss some files.

```bash
qdirstat-cache-writer -l / /tmp/qdirstat-$USER/root.cache.gz
```

--------------------------------

### Create and Configure a Dedicated Trash Directory

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Troubleshooting.md

Use these commands to create a dedicated trash directory on a specific filesystem mount point. Ensure the directory has the correct permissions (01777) as required by the XDG trash specification.

```bash
cd /data
sudo mkdir .Trash
sudo chmod 01777 .Trash
```

--------------------------------

### Integrate Package Manager with PkgFilter

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Use PkgFilter to select packages and PkgManager to query file ownership and lists. Requires the PkgFilter and PkgManager headers.

```cpp
#include "PkgFilter.h"
#include "PkgManager.h"
#include "PkgInfo.h"
#include "DirTree.h"

// Create package filter with pattern
QDirStat::PkgFilter filter("chromium");  // Starts with "chromium"

// Different filter modes (auto-detected from pattern)
QDirStat::PkgFilter exactFilter("=emacs");           // Exact match
QDirStat::PkgFilter wildcardFilter("*gtk*");         // Wildcard
QDirStat::PkgFilter regexFilter(".*qt[45].*");       // Regex
QDirStat::PkgFilter allFilter("");                   // All packages

// Access filter properties
QString pattern = filter.pattern();
QDirStat::PkgFilter::FilterMode mode = filter.filterMode();
// Modes: Auto, Contains, StartsWith, ExactMatch, Wildcard, RegExp

// Read packages into DirTree
QDirStat::DirTree * tree = new QDirStat::DirTree();
tree->readPkg(filter);

// Check if a package manager is available
QDirStat::PkgManager * pkgManager = QDirStat::PkgManager::primary();
if (pkgManager && pkgManager->isPrimaryPkgManager()) {
    qDebug() << "Primary package manager:" << pkgManager->name();

    // Get file list for a package
    QStringList files = pkgManager->fileList("chromium-browser");

    // Check which package owns a file
    QString pkg = pkgManager->owningPkg("/usr/bin/chromium");
}

// Query unpackaged files view (excludes packaged files)
// Use "unpkg:/usr/share" URL or menu "File" -> "Show Unpackaged Files"
// Configuration stored in ~/.config/QDirStat/QDirStat.conf:
// [Pkg]
// MaxParallelProcesses=6
// MinCachePkgListSize=200
```

--------------------------------

### List shadowed files with tree

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Use tree to visualize the directory structure of shadowed files.

```console
root@linux:~# tree /mnt/shadowed
```

--------------------------------

### Show Btrfs Filesystem Disk Free

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Btrfs-Free-Size.md

Use `btrfs filesystem df` with root permissions to show a summarized view of disk space usage for different Btrfs data types. Provide the mount point as an argument.

```bash
sudo btrfs filesystem df /mybtrfs
```

```bash
sudo btrfs fi df /mybtrfs
```

--------------------------------

### Retrieve Package File List

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Pkg-View.md

Commands used to list files associated with a specific package.

```bash
dpkg-query --listfiles pkgname
```

```bash
rpm -ql pkgname
```

```bash
pacman -Qlq pkgname
```

--------------------------------

### Generate QDirStat Cache File

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

Use the qdirstat-cache-writer script to generate a cache file for QDirStat. This can speed up analysis of large, infrequently changing directories.

```bash
qdirstat-cache-writer -l
```

--------------------------------

### Find Mounted Filesystems with findmnt

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Use `findmnt` to show the mount hierarchy of all mounted filesystems. It can filter by filesystem type and does not require root permissions.

```console
sh@balrog:~$ findmnt -t ext4,ext3,ext2,xfs,btrfs,fuseblk,vfat,vboxsf
TARGET            SOURCE    FSTYPE  OPTIONS
/                 /dev/sdc2 ext4    rw,relatime,errors=remount-ro,data=ordered
├─/hd-root-14-04  /dev/sdb3 ext4    rw,relatime,data=ordered
├─/hd-root-18-04  /dev/sdb2 ext4    rw,relatime,data=ordered
├─/ssd-root-20-04 /dev/sdc3 ext4    rw,relatime,data=ordered
├─/ssd-work       /dev/sdc4 ext4    rw,relatime,data=ordered
├─/win/boot       /dev/sda1 fuseblk rw,relatime,user_id=0,group_id=0,default_permissions,allow_other
├─/win/app        /dev/sda2 fuseblk rw,relatime,user_id=0,group_id=0,default_permissions,allow_other
└─/work           /dev/sdb5 ext4    rw,relatime,data=ordered
```

```console
tux@linux:~> findmnt -t ext4,ext3,ext2,xfs,btrfs,fuseblk,vfat,vboxsf
TARGE                   SOURCE                              FSTYPE OPTIONS
/                       /dev/sda2[/@]                       btrfs  rw,relatime,space_cache,subvolid=256,subvol=/@
├─/opt                  /dev/sda2[/@/opt]                   btrfs  rw,relatime,space_cache,subvolid=262,subvol=/@/opt
├─/boot/grub2/i386-pc   /dev/sda2[/@/boot/grub2/i386-pc]    btrfs  rw,relatime,space_cache,subvolid=264,subvol=/@/boot/grub2/i386-pc
├─/boot/grub2/x86_64-efi /dev/sda2[/@/boot/grub2/x86_64-efi] btrfs  rw,relatime,space_cache,subvolid=263,subvol=/@/boot/grub2/x86_64-efi
├─/var                  /dev/sda2[/@/var]                   btrfs  rw,relatime,space_cache,subvolid=258,subvol=/@/var
├─/root                 /dev/sda2[/@/root]                  btrfs  rw,relatime,space_cache,subvolid=261,subvol=/@/root
├─/srv                  /dev/sda2[/@/srv]                   btrfs  rw,relatime,space_cache,subvolid=260,subvol=/@/srv
├─/usr/local            /dev/sda2[/@/usr/local]             btrfs  rw,relatime,space_cache,subvolid=259,subvol=/@/usr/local
├─/work/tmp             work_tmp                            vboxsf rw,nodev,relatime
├─/work/src             work_src                            vboxsf rw,nodev,relatime
└─/home                 /dev/sda4                           ext4   rw,relatime,data=ordered
```

--------------------------------

### View Cache File Data with QDirStat

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Open the transferred cache file using QDirStat on your desktop machine via the command line or the 'File' menu.

```bash
qdirstat --cache ~/tmp/myserver-root.cache.gz
```

```bash
qdirstat -c ~/tmp/myserver-root.cache.gz
```

--------------------------------

### Apply Review Feedback

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/GitHub-Workflow.md

Switches to the pull request branch to incorporate requested changes and pushes them to the fork.

```bash
git checkout kilroy-transmogrify
...(add requested fixes...)
git commit -am "Added code review changes"
git push mine kilroy-transmogrify
```

--------------------------------

### Generate Cache Files with qdirstat-cache-writer

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Use this Perl script to generate cache files for remote servers or headless environments. Files can be compressed with gzip if the .gz extension is used.

```bash
# Basic usage - write cache to default location (.qdirstat.cache.gz in target directory)
qdirstat-cache-writer /home/user

# Write to specific cache file (auto-compressed if .gz extension)
qdirstat-cache-writer /srv/data /tmp/srv-data.cache.gz

# Long format - include full paths for all entries (useful with zgrep as locate replacement)
qdirstat-cache-writer -l /home /tmp/home-full.cache.gz

# File format 1.0 without UID/GID/permissions (smaller files)
qdirstat-cache-writer -1 /var/log /tmp/varlog.cache.gz

# File format 2.0 with UID/GID/permissions (default)
qdirstat-cache-writer -2 /etc /tmp/etc.cache.gz

# Scan mounted filesystems (cross filesystem boundaries)
qdirstat-cache-writer -m / /tmp/full-root.cache.gz

# Ignore directory own size (useful for CephFS)
qdirstat-cache-writer -i /ceph/data /tmp/ceph.cache.gz

# Verbose output
qdirstat-cache-writer -v /home/user /tmp/user.cache.gz

# Debug mode
qdirstat-cache-writer -d /srv /tmp/srv.cache.gz

# Combine options
qdirstat-cache-writer -l -v -2 /var /tmp/var-detailed.cache.gz
```

--------------------------------

### List Real Mounts from /proc/mounts

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Filters `/proc/mounts` to show only actual data mounts, excluding system directories like `/sys`, `/proc`, `/dev`, `/run`, and bind-mounts in `/mnt`.

```bash
root@linux:~# egrep -v ' /(sys|proc|dev|run|mnt)' /proc/mounts
/dev/sdc2 / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0
/dev/sdb2 /hd-root-18-04 ext4 rw,relatime,data=ordered 0 0
/dev/sdb3 /hd-root-14-04 ext4 rw,relatime,data=ordered 0 0
/dev/sdc3 /ssd-root-20-04 ext4 rw,relatime,data=ordered 0 0
/dev/sdc4 /ssd-work ext4 rw,relatime,data=ordered 0 0
/dev/sda1 /win/boot fuseblk rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0
/dev/sdb5 /work ext4 rw,relatime,data=ordered 0 0
/dev/sda2 /win/app fuseblk rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0
```

--------------------------------

### Specify Cache File at Command Line

Source: https://github.com/shundhammer/qdirstat/blob/master/README.md

You can specify a cache file to be read directly by QDirStat using the --cache option.

```bash
qdirstat --cache cache-file
```

--------------------------------

### View QDirStat Cache File with zless

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Use 'zless' to view the contents of a gzipped QDirStat cache file. This is useful for inspecting the file format and its entries.

```bash
[qdirstat 1.0 cache file]
# Generated by qdirstat-cache-writer
# Do not edit!
#
# Type  path            size    mtime           <optional fields>

D /var  4096    0x53cef170
# Device: /dev/sda6

L       run     4       0x54bbf0e3
L       lock    9       0x54bbf0e3
D /var/cache    4096    0x58125237
D /var/cache/dictionaries-common        4096    0x53ceef0a
F       hunspell.db     188     0x53ceef0a
F       ispell-dicts-list.txt   0       0x53ceef0a
F       wordlist.db     267     0x53cef022
F       ispell.db       188     0x53ceef0a
F       jed-ispell-dicts.sl     881     0x53cef024
F       aspell.db       741     0x53cef024
F       sqspell.php     366     0x53cef024
F       emacsen-ispell-default.el       173     0x53ceef0a
F       emacsen-ispell-dicts.el 897     0x53cef024
D /var/cache/cracklib   4096    0x53ceef8b
F       cracklib_dict.pwi       22972   0x53ceef8b
F       cracklib_dict.hwm       1024    0x53ceef8b
F       src-dicts       104     0x53ceef8b
F       cracklib_dict.pwd       412618  0x53ceef8b
D /var/cache/cups       4096    0x58a842ad
F       job.cache       992     0x58a842ad
F       ppd-updates     271     0x567b004a
```

--------------------------------

### Configure Custom Cleanup Actions

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Defines shell command execution for files or directories with support for variable expansion and refresh policies.

```cpp
#include "Cleanup.h"
#include "CleanupCollection.h"

// Create a custom cleanup action
QDirStat::Cleanup * cleanup = new QDirStat::Cleanup(
    "tar cjf '%n.tar.bz2' '%n' && rm -rf '%n'",  // Command
    "Compress and Delete",                        // Menu title
    parent
);

// Configure the cleanup
cleanup->setActive(true);
cleanup->setWorksForDir(true);
cleanup->setWorksForFile(false);
cleanup->setWorksForDotEntry(false);
cleanup->setRecurse(false);
cleanup->setAskForConfirmation(true);

// Set refresh policy after execution
cleanup->setRefreshPolicy(QDirStat::Cleanup::RefreshParent);
// Options: NoRefresh, RefreshThis, RefreshParent, AssumeDeleted

// Configure output window behavior
cleanup->setOutputWindowPolicy(QDirStat::Cleanup::ShowAfterTimeout);
// Options: ShowAlways, ShowIfErrorOutput, ShowAfterTimeout, ShowNever
cleanup->setOutputWindowTimeout(3000);  // 3 seconds
cleanup->setOutputWindowAutoClose(true);

// Set shell (default uses $SHELL, fallback to /bin/bash, then /bin/sh)
cleanup->setShell("/bin/bash");

// Set icon
cleanup->setIcon("archive");

// Variable expansion in commands:
// %p - Full path in single quotes: '/home/user/Documents/file.txt'
// %n - Name only in single quotes: 'file.txt'
// %d - Directory path: '/home/user/Documents'
// %terminal - Desktop terminal: konsole, gnome-terminal, xfce4-terminal
// %filemanager - Desktop file manager: dolphin, nautilus, thunar

// Example cleanup commands:
// "xdg-open %p"                           - Open with default app
// "%terminal --workdir %d"                - Open terminal here
// "%filemanager %d"                       - Open file manager here
// "rm -rf %p"                             - Delete immediately
// "gzip -9 %p"                            - Compress file
// "convert %p -resize 50%% %p"            - Resize image

// Execute the cleanup on a FileInfo item
cleanup->execute(fileInfo, outputWindow);
```

--------------------------------

### Bind-Mount a Single Directory

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Performs a bind-mount of `/mnt/root/work` to `/mnt/shadowed/work`, making the contents of the former accessible at the latter.

```bash
root@linux:~# mount -o bind /mnt/root/work /mnt/shadowed/work
```

--------------------------------

### Create QDirStat Cache with Exclusions

Source: https://github.com/shundhammer/qdirstat/blob/master/scripts/pkg-tools/README.md

Excludes a list of files from an uncompressed QDirStat cache file. The script reads from stdin and writes to stdout. Input must be uncompressed.

```bash
zcat qdirstat-cache.gz | ./cache-exclude exclude-file | gzip >result-cache.gz
```

--------------------------------

### View Git Remotes

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/GitHub-Workflow.md

Verify the configured remotes ('mine' and 'upstream') for your local repository. This command lists all remote connections and their associated URLs.

```bash
git remote -v
```

--------------------------------

### Find shadowed files with find

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Use find to locate all files within the shadowed directory.

```console
root@linux:~# find /mnt/shadowed -type f
```

--------------------------------

### Access Filesystem Metadata with FileInfo

Source: https://context7.com/shundhammer/qdirstat/llms.txt

The FileInfo class provides methods to retrieve file attributes, size metrics, ownership, and tree navigation data. It is designed for high-performance access during large-scale filesystem scans.

```cpp
#include "FileInfo.h"
#include "DirInfo.h"

// Access file properties from a FileInfo pointer
void analyzeFile(QDirStat::FileInfo * item) {
    // Basic identification
    QString name = item->name();           // Filename without path
    QString fullPath = item->url();        // Complete path
    QString baseName = item->baseName();   // Last path component

    // File type checks
    if (item->isDir())      { /* Directory */ }
    if (item->isFile())     { /* Regular file */ }
    if (item->isSymLink())  { /* Symbolic link */ }
    if (item->isDevice())   { /* Block or character device */ }
    if (item->isSparseFile()) { /* File with holes */ }
    if (item->isBrokenSymLink()) { /* Broken symlink */ }

    // Size information
    QDirStat::FileSize size = item->size();              // Logical size (respects hard links)
    QDirStat::FileSize rawSize = item->rawByteSize();    // Raw byte size
    QDirStat::FileSize allocated = item->allocatedSize(); // Actual disk allocation
    QDirStat::FileSize blocks = item->blocks();          // 512-byte blocks

    // For directories/subtrees
    QDirStat::FileSize totalSize = item->totalSize();
    int totalFiles = item->totalFiles();
    int totalSubDirs = item->totalSubDirs();
    int totalItems = item->totalItems();

    // Timestamps
    time_t mtime = item->mtime();
    short year = item->mtimeYear();   // 1970-2037
    short month = item->mtimeMonth(); // 1-12

    // Ownership and permissions
    if (item->hasUid()) {
        uid_t uid = item->uid();
        QString userName = item->userName();
    }
    if (item->hasGid()) {
        gid_t gid = item->gid();
        QString groupName = item->groupName();
    }
    if (item->hasPermissions()) {
        QString symbolic = item->symbolicPermissions(); // "-rwxr-xr-x"
        QString octal = item->octalPermissions();       // "0755"
    }

    // Tree navigation
    QDirStat::DirInfo * parent = item->parent();
    QDirStat::FileInfo * sibling = item->next();
    QDirStat::DirTree * tree = item->tree();
    int depth = item->treeLevel();

    // Percentage of parent
    float percent = item->subtreePercent();
}
```

--------------------------------

### Make Script Executable

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Grant execute permissions to the downloaded `unshadow-mount-points` script using `chmod`. This allows the script to be run directly from the command line.

```bash
tux@linux:~/tmp> chmod 755 unshadow-mount-points
```

--------------------------------

### List Btrfs Subvolumes on Root Device

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Shows all entries in `/proc/mounts` that use the specified root device, useful for identifying Btrfs subvolumes.

```bash
tux@linux:~> grep $ROOT_DEVICE /proc/mounts
/dev/sda2 / btrfs rw,relatime,space_cache,subvolid=256,subvol=/@ 0 0
/dev/sda2 /boot/grub2/i386-pc btrfs rw,relatime,space_cache,subvolid=264,subvol=/@/boot/grub2/i386-pc 0 0
/dev/sda2 /boot/grub2/x86_64-efi btrfs rw,relatime,space_cache,subvolid=263,subvol=/@/boot/grub2/x86_64-efi 0 0
/dev/sda2 /opt btrfs rw,relatime,space_cache,subvolid=262,subvol=/@/opt 0 0
/dev/sda2 /var btrfs rw,relatime,space_cache,subvolid=258,subvol=/@/var 0 0
/dev/sda2 /root btrfs rw,relatime,space_cache,subvolid=261,subvol=/@/root 0 0
/dev/sda2 /srv btrfs rw,relatime,space_cache,subvolid=260,subvol=/@/srv 0 0
/dev/sda2 /usr/local btrfs rw,relatime,space_cache,subvolid=259,subvol=/@/usr/local 0 0
```

--------------------------------

### Manage Directory Trees with DirTree

Source: https://context7.com/shundhammer/qdirstat/llms.txt

Use the DirTree class to initiate directory scans, handle caching, and navigate the resulting tree structure. Ensure proper signal connections are established to monitor the asynchronous reading process.

```cpp
#include "DirTree.h"
#include "FileInfo.h"
#include "DirInfo.h"

// Create and start reading a directory tree
QDirStat::DirTree * tree = new QDirStat::DirTree();

// Connect signals for progress updates
connect(tree, &QDirStat::DirTree::startingReading,
        this, &MyClass::onStartReading);
connect(tree, &QDirStat::DirTree::finished,
        this, &MyClass::onReadingFinished);
connect(tree, &QDirStat::DirTree::aborted,
        this, &MyClass::onReadingAborted);
connect(tree, &QDirStat::DirTree::progressInfo,
        this, &MyClass::onProgressInfo);

// Start reading from a path
tree->startReading("/home/user/Documents");

// Or read from a cache file
tree->clearAndReadCache("/tmp/server.cache.gz");

// Configure filesystem boundary crossing (default: false)
tree->setCrossFilesystems(false);

// Access the tree structure
QDirStat::DirInfo * root = tree->root();
QDirStat::FileInfo * topLevel = tree->firstToplevel();
QString device = tree->device(); // e.g., "/dev/sda1"

// Locate a file by path
QDirStat::FileInfo * item = tree->locate("/home/user/Documents/file.txt");
if (item) {
    qDebug() << "Found:" << item->url() << "Size:" << item->size();
}

// Refresh a subtree
tree->refresh(someDirInfo);

// Write cache file for later use
tree->writeCache("/tmp/documents.cache.gz");

// Check reading state
if (tree->isBusy()) {
    tree->abortReading();
}

// Clean up
delete tree;
```

--------------------------------

### Identify Bind Mount Limitations

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/Shadowed-by-Mount.md

Demonstration of errors encountered when attempting to remove active bind mount points.

```console
tux@linux:~/tmp> sudo rm -rf /mnt/shadowed/work_tmp
rm: cannot remove '/mnt/shadowed/work_tmp': Device or resource busy
tux@linux:~/tmp> sudo mv /mnt/shadowed/work_tmp .
mv: cannot remove '/mnt/shadowed/work_tmp': Device or resource busy
```

--------------------------------

### Transfer Cache Files to Desktop

Source: https://github.com/shundhammer/qdirstat/blob/master/doc/QDirStat-for-Servers.md

Use scp to copy the generated cache files from the server to your local desktop machine.

```bash
scp "root@myserver:~/tmp/*.cache.gz" ~/tmp
```