### Install Executable

Source: https://github.com/nixos/patchelf/blob/master/src/CMakeLists.txt

Installs the compiled patchelf executable to the standard binary directory.

```cmake
install(TARGETS patchelf RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
```

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

### Build with Meson and Ninja

Source: https://github.com/nixos/patchelf/blob/master/README.md

Build process using Meson with the Ninja generator.

```console
mkdir build
meson configure build
cd build
ninja all
sudo ninja install
```

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

### Build with CMake and Ninja

Source: https://github.com/nixos/patchelf/blob/master/README.md

Build process using CMake with the Ninja generator.

```console
mkdir build
cd build
cmake .. -GNinja
ninja all
sudo ninja install
```

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

### Manage Dependencies

Source: https://github.com/nixos/patchelf/blob/master/README.md

Remove, add, or replace DT_NEEDED entries for dynamic libraries.

```console
$ patchelf --remove-needed libfoo.so.1 my-program
```

```console
$ patchelf --add-needed libfoo.so.1 my-program
```

```console
$ patchelf --replace-needed liboriginal.so.1 libreplacement.so.1 my-program
```

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

### Build with Autotools

Source: https://github.com/nixos/patchelf/blob/master/README.md

Standard build sequence for GNU Autotools projects.

```console
./bootstrap.sh
./configure
make
make check
sudo make install
```

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

### Set RPATH/RUNPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Configure the library search path for an executable. Use $ORIGIN for relative paths or --force-rpath to use the obsolete DT_RPATH instead of DT_RUNPATH.

```bash
# Print current RPATH/RUNPATH
patchelf --print-rpath my-program
# Output: /usr/local/lib:/opt/mylibs

# Set a new RPATH (replaces existing)
patchelf --set-rpath '/opt/my-libs/lib:/other-libs' my-program

# Use $ORIGIN for relocatable binaries (path relative to executable)
patchelf --set-rpath '$ORIGIN/../lib:$ORIGIN/../lib64' my-program

# Set multiple library search paths
patchelf --set-rpath '/app/lib:/app/vendor/lib:/usr/local/lib' my-program

# Force use of obsolete DT_RPATH instead of DT_RUNPATH
# (DT_RPATH affects child dependencies, DT_RUNPATH doesn't)
patchelf --force-rpath --set-rpath '/opt/legacy/lib' my-program

# Read rpath from file
echo '/opt/generated/lib:/usr/lib' > rpath.txt
patchelf --set-rpath @rpath.txt my-program
```

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

### Set Compile Definitions

Source: https://github.com/nixos/patchelf/blob/master/src/CMakeLists.txt

Adds preprocessor definitions to the patchelf target, including page size and package version string.

```cmake
target_compile_definitions(
  patchelf PRIVATE PAGESIZE=${PAGESIZE}
                   PACKAGE_STRING="patchelf ${VERSION_STRING}")
```

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

### Change SONAME

Source: https://github.com/nixos/patchelf/blob/master/README.md

Update the SONAME of a dynamic library.

```console
$ patchelf --set-soname libnewname.so.3.4.5 path/to/libmylibrary.so.1.2.3
```

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

### Print rpath

Source: https://context7.com/nixos/patchelf/llms.txt

Prints the runtime search path (RPATH) of an executable. An empty output indicates no RPATH is set.

```bash
patchelf --print-rpath my-program
```

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

### Control Default Library Search Paths

Source: https://context7.com/nixos/patchelf/llms.txt

Marks an object to ignore default library search paths, making it rely solely on RPATH/RUNPATH and LD_LIBRARY_PATH. This is useful for creating fully self-contained applications.

```bash
# Mark binary to ignore default library paths
patchelf --no-default-lib my-program
```

```bash
patchelf --set-rpath '$ORIGIN/lib' --no-default-lib my-app
```

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

### Set C++ Standard and Extensions

Source: https://github.com/nixos/patchelf/blob/master/src/CMakeLists.txt

Configures the C++ standard to C++17 and disables language extensions for stricter compliance.

```cmake
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_EXTENSIONS OFF)
```

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

### Add Executable Target

Source: https://github.com/nixos/patchelf/blob/master/src/CMakeLists.txt

Defines the main executable for the project, linking source files.

```cmake
add_executable(${PROJECT_NAME} patchelf.cc elf.h patchelf.h)
```

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

### Enable Debug Mode

Source: https://context7.com/nixos/patchelf/llms.txt

Enables verbose output detailing the modifications being made to the ELF file. This is helpful for troubleshooting and understanding the tool's behavior. Debug mode can also be enabled via the PATCHELF_DEBUG environment variable.

```bash
# Enable debug output
patchelf --debug --set-rpath /opt/lib my-program
```

```bash
# Can also be enabled via environment variable
PATCHELF_DEBUG=1 patchelf --set-interpreter /lib/ld.so my-program
```

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

### Set ELF Interpreter

Source: https://context7.com/nixos/patchelf/llms.txt

Modify the dynamic loader path for an executable. Use the @ prefix to read the path from a file or --output to save to a new file.

```bash
# Print current interpreter
patchelf --print-interpreter my-program
# Output: /lib64/ld-linux-x86-64.so.2

# Set a new interpreter
patchelf --set-interpreter /opt/custom-glibc/lib/ld-linux-x86-64.so.2 my-program

# Set interpreter with a very long path (patchelf handles resizing automatically)
patchelf --set-interpreter /very/long/path/to/custom/lib64/ld-linux-x86-64.so.2 my-program

# Use --output to preserve the original file
patchelf --set-interpreter /lib/my-ld-linux.so.2 --output my-program-patched my-program

# Read interpreter path from a file using @ prefix
echo "/opt/custom/lib/ld-linux.so.2" > interpreter.txt
patchelf --set-interpreter @interpreter.txt my-program
```

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

### Define Page Size

Source: https://github.com/nixos/patchelf/blob/master/src/CMakeLists.txt

Sets a constant for page size, likely used in memory management or file operations.

```cmake
set(PAGESIZE 4096)
```

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

### Set OS ABI

Source: https://context7.com/nixos/patchelf/llms.txt

Changes the OS ABI field (EI_OSABI) in the ELF header, affecting how the operating system loads and interprets the binary. Supported values include System V, Linux, FreeBSD, NetBSD, OpenBSD, Solaris, and others.

```bash
# Print current OS ABI
patchelf --print-os-abi my-program
```

```bash
# Set OS ABI to System V (generic UNIX)
patchelf --set-os-abi "System V" my-program
```

```bash
# Set to specific operating system
patchelf --set-os-abi Linux my-program
patchelf --set-os-abi FreeBSD my-program
patchelf --set-os-abi NetBSD my-program
patchelf --set-os-abi OpenBSD my-program
patchelf --set-os-abi Solaris my-program
```

```bash
# Case-insensitive matching works
patchelf --set-os-abi linux my-program
patchelf --set-os-abi LINUX my-program
```

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

### Set Interpreter

Source: https://context7.com/nixos/patchelf/llms.txt

Changes the dynamic loader (ELF interpreter) of an executable. This is useful for relocating binaries or using custom library paths.

```APIDOC
## Set Interpreter

### Description
Changes the dynamic loader (ELF interpreter) of an executable. This is useful when you need to use a different C library or dynamic linker, such as when relocating binaries or using custom library paths. The interpreter is the program that loads and prepares an executable for running.

### Method
`patchelf`

### Parameters
#### Command Line Arguments
- `--print-interpreter` - Prints the current interpreter path.
- `--set-interpreter <path>` - Sets a new interpreter path. Can be a direct path or a file path prefixed with `@`.
- `--output <output_file>` - Specifies an output file to preserve the original binary.

### Request Example
```bash
# Print current interpreter
patchelf --print-interpreter my-program

# Set a new interpreter
patchelf --set-interpreter /opt/custom-glibc/lib/ld-linux-x86-64.so.2 my-program

# Set interpreter with a very long path
patchelf --set-interpreter /very/long/path/to/custom/lib64/ld-linux-x86-64.so.2 my-program

# Use --output to preserve the original file
patchelf --set-interpreter /lib/my-ld-linux.so.2 --output my-program-patched my-program

# Read interpreter path from a file using @ prefix
echo "/opt/custom/lib/ld-linux.so.2" > interpreter.txt
patchelf --set-interpreter @interpreter.txt my-program
```

### Response Example
```
# Output of --print-interpreter
/lib64/ld-linux-x86-64.so.2
```
```

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

### Shrink RPATH

Source: https://github.com/nixos/patchelf/blob/master/README.md

Remove unnecessary directories from the RPATH. Use --allowed-rpath-prefixes to preserve specific paths.

```console
$ patchelf --shrink-rpath my-program
```

```console
$ patchelf --shrink-rpath --allowed-rpath-prefixes /usr/lib:/foo/lib my-program
```

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

### Add RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Appends a new directory to the existing DT_RUNPATH without replacing it.

```APIDOC
## Add RPATH

### Description
Appends a new directory to the existing DT_RUNPATH without replacing it. This is useful when you need to add additional library search paths while preserving the original ones.

### Method
`patchelf`

### Parameters
#### Command Line Arguments
- `--print-rpath` - Prints the current RPATH.
- `--add-rpath <path>` - Appends a new directory to the existing RPATH.
- `--output <output_file>` - Specifies an output file to preserve the original binary.

### Request Example
```bash
# Print current RPATH
patchelf --print-rpath my-program

# Add a new path to existing RPATH
patchelf --add-rpath /opt/newlibs my-program

# Print RPATH after modification
patchelf --print-rpath my-program

# Add multiple paths (run multiple times or use colon-separated in some versions)
patchelf --add-rpath /app/lib my-program
patchelf --add-rpath /vendor/lib my-program
```

### Response Example
```
# Output of --print-rpath after adding /opt/newlibs
/usr/local/lib:/opt/newlibs
```
```

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

### Perform Combined Operations

Source: https://context7.com/nixos/patchelf/llms.txt

Allows multiple ELF modifications in a single command invocation for efficiency and atomic updates. This is useful for complex relocations, preparing libraries for distribution, or fixing binaries for custom environments.

```bash
# Complete binary relocation in one command
patchelf \
  --set-interpreter '$ORIGIN/../lib/ld-linux-x86-64.so.2' \
  --set-rpath '$ORIGIN/../lib' \
  --replace-needed libc.so.6 '$ORIGIN/../lib/libc.so.6' \
  my-program
```

```bash
# Prepare library for distribution
patchelf \
  --set-soname libmyapp.so.1 \
  --set-rpath '$ORIGIN' \
  --remove-needed libdevel.so \
  --clear-execstack \
  libmyapp.so.1.2.3
```

```bash
# Fix binary for custom environment
patchelf \
  --set-interpreter /opt/glibc-2.31/lib/ld-linux-x86-64.so.2 \
  --set-rpath /opt/glibc-2.31/lib:/opt/myapp/lib \
  --add-needed libcustom.so \
  --output my-program-patched \
  my-program
```

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

### Modify RPATH

Source: https://github.com/nixos/patchelf/blob/master/README.md

Set the RPATH for executables and libraries.

```console
$ patchelf --set-rpath /opt/my-libs/lib:/other-libs my-program
```

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

### Modify ELF Interpreter

Source: https://github.com/nixos/patchelf/blob/master/README.md

Change the dynamic loader of an executable.

```console
$ patchelf --set-interpreter /lib/my-ld-linux.so.2 my-program
```

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

### Add RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Append a directory to the existing DT_RUNPATH without overwriting current entries.

```bash
# Print current RPATH
patchelf --print-rpath my-program
# Output: /usr/local/lib

# Add a new path to existing RPATH
patchelf --add-rpath /opt/newlibs my-program

# Print RPATH after modification
patchelf --print-rpath my-program
# Output: /usr/local/lib:/opt/newlibs

# Add multiple paths (run multiple times or use colon-separated in some versions)
patchelf --add-rpath /app/lib my-program
patchelf --add-rpath /vendor/lib my-program
```

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

### Replace Needed Library Dependency

Source: https://context7.com/nixos/patchelf/llms.txt

Replaces a declared dependency on one library with another. This is useful for redirecting dependencies to alternative implementations, newer versions, or different library locations.

```bash
# Print current dependencies
patchelf --print-needed my-program
```

```bash
# Replace one library with another
patchelf --replace-needed libssl.so.1.0.0 libssl.so.1.1 my-program
```

```bash
# Replace with absolute path
patchelf --replace-needed libfoo.so /opt/custom/lib/libfoo-custom.so my-program
```

```bash
# Multiple replacements in one command
patchelf \
  --replace-needed libold1.so libnew1.so \
  --replace-needed libold2.so libnew2.so \
  my-program
```

```bash
# Combine with other operations
patchelf \
  --replace-needed libc.so.6 /opt/glibc/lib/libc.so.6 \
  --add-needed /opt/extra/libextra.so \
  --set-rpath '/opt/glibc/lib:/opt/extra' \
  my-program
```

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

### Rename Dynamic Symbols

Source: https://context7.com/nixos/patchelf/llms.txt

Renames dynamic symbols in the binary using a mapping file. This is useful for symbol interposition, ABI compatibility fixes, or redirecting function calls to alternative implementations.

```bash
# Create a symbol mapping file (space-separated: old_name new_name)
cat > symbol_map.txt << 'EOF'
malloc custom_malloc
free custom_free
open custom_open
write custom_write
EOF
```

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

### Output Modifications to a Different File

Source: https://context7.com/nixos/patchelf/llms.txt

Writes ELF file modifications to a specified output file instead of modifying the input file in place. This preserves the original binary and is useful for testing or creating patched versions.

```bash
# Modify and write to new file
patchelf --set-interpreter /lib/ld-linux.so.2 --output modified-program original-program
```

```bash
# Create patched version without modifying original
patchelf \
  --set-rpath '$ORIGIN/lib' \
  --replace-needed libssl.so.1.0 libssl.so.1.1 \
  --output app-patched \
  app-original
```

```bash
# Useful for creating distribution packages
cp my-app my-app.orig
patchelf --set-rpath '$ORIGIN/../lib' --output my-app my-app.orig
```

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

### Set RPATH/RUNPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Changes or sets the DT_RUNPATH (or DT_RPATH) of executables and libraries to control where the dynamic linker searches for shared libraries at runtime.

```APIDOC
## Set RPATH/RUNPATH

### Description
Changes or sets the DT_RUNPATH (or DT_RPATH) of executables and libraries to control where the dynamic linker searches for shared libraries at runtime. RUNPATH is the modern replacement for RPATH with the advantage that it can be overridden by LD_LIBRARY_PATH and is scoped to the current binary only.

### Method
`patchelf`

### Parameters
#### Command Line Arguments
- `--print-rpath` - Prints the current RPATH/RUNPATH.
- `--set-rpath <paths>` - Sets a new RPATH/RUNPATH. Paths should be colon-separated. Can use `$ORIGIN` for relative paths. Can read paths from a file prefixed with `@`.
- `--force-rpath` - Forces the use of obsolete DT_RPATH instead of DT_RUNPATH.
- `--output <output_file>` - Specifies an output file to preserve the original binary.

### Request Example
```bash
# Print current RPATH/RUNPATH
patchelf --print-rpath my-program

# Set a new RPATH (replaces existing)
patchelf --set-rpath '/opt/my-libs/lib:/other-libs' my-program

# Use $ORIGIN for relocatable binaries (path relative to executable)
patchelf --set-rpath '$ORIGIN/../lib:$ORIGIN/../lib64' my-program

# Set multiple library search paths
patchelf --set-rpath '/app/lib:/app/vendor/lib:/usr/local/lib' my-program

# Force use of obsolete DT_RPATH instead of DT_RUNPATH
patchelf --force-rpath --set-rpath '/opt/legacy/lib' my-program

# Read rpath from file
echo '/opt/generated/lib:/usr/lib' > rpath.txt
patchelf --set-rpath @rpath.txt my-program
```

### Response Example
```
# Output of --print-rpath
/usr/local/lib:/opt/mylibs
```
```

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

### Add Needed Library Dependency

Source: https://context7.com/nixos/patchelf/llms.txt

Adds a new DT_NEEDED entry to declare a dependency on a shared library. This is useful for permanently adding library dependencies that were not linked at build time, such as LD_PRELOAD libraries.

```bash
# Print current needed libraries
patchelf --print-needed my-program
```

```bash
# Add a new library dependency
patchelf --add-needed libbar.so.1 my-program
```

```bash
# Add multiple dependencies
patchelf --add-needed libextra.so.1 my-program
patchelf --add-needed libhelper.so.2 my-program
```

```bash
# Verify the addition
patchelf --print-needed my-program
```

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

### Add DT_DEBUG Tag

Source: https://context7.com/nixos/patchelf/llms.txt

Adds a DT_DEBUG tag to the .dynamic section of a shared library if it's not already present. This is crucial for enabling proper debugger support, especially when the library can be run as an executable.

```bash
# Add DT_DEBUG tag to a shared library with entry point
patchelf --add-debug-tag libmylib.so
```

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

### Rename Dynamic Symbols

Source: https://context7.com/nixos/patchelf/llms.txt

Renames dynamic symbols in an ELF file based on a provided map. Use a file with 'old_name new_name' per line for multiple renames, or pipe 'old_name new_name' for a single rename.

```bash
# Rename symbols according to the map
patchelf --rename-dynamic-symbols symbol_map.txt my-program
```

```bash
# Single symbol rename
echo "old_function new_function" > single_map.txt
patchelf --rename-dynamic-symbols single_map.txt libmylib.so
```

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

### Override ELF Page Size

Source: https://context7.com/nixos/patchelf/llms.txt

Overrides the default page size used when modifying ELF files. This is useful for architectures with non-standard page sizes or when default detection fails.

```bash
# Use custom page size (in bytes)
patchelf --page-size 4096 --set-rpath /opt/lib my-program
```

```bash
# For architectures with larger page sizes (e.g., 64KB pages)
patchelf --page-size 65536 --set-interpreter /lib/ld.so my-program
```

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

### Remove RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Completely delete the DT_RPATH or DT_RUNPATH entry from the binary.

```bash
# Check current RPATH
patchelf --print-rpath my-program
# Output: /custom/lib:/usr/local/lib

# Remove RPATH entirely
patchelf --remove-rpath my-program
```

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

### Shrink RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Removes from the RPATH all directories that do not contain a library referenced by DT_NEEDED entries.

```APIDOC
## Shrink RPATH

### Description
Removes from the RPATH all directories that do not contain a library referenced by DT_NEEDED entries. This optimization reduces unnecessary directory searches and cleans up build artifacts like temporary build directories from the library search path.

### Method
`patchelf`

### Parameters
#### Command Line Arguments
- `--shrink-rpath` - Shrinks the RPATH by removing unused directories.
- `--allowed-rpath-prefixes <prefixes>` - Optional. Specifies prefixes to keep during shrinking, useful for preserving system paths.
- `--output <output_file>` - Specifies an output file to preserve the original binary.

### Request Example
```bash
# Before: RPATH might contain build directories
patchelf --print-rpath my-program

# Shrink RPATH to only directories containing needed libraries
patchelf --shrink-rpath my-program

# After: Only directories with actual needed libraries remain
patchelf --print-rpath my-program

# Shrink RPATH but only allow certain prefixes
patchelf --shrink-rpath --allowed-rpath-prefixes /usr/lib:/opt/mylibs my-program

# This removes /tmp/build entries but keeps /usr and /opt paths
patchelf --shrink-rpath --allowed-rpath-prefixes /usr:/opt my-program
```

### Response Example
```
# Output of --print-rpath after shrinking
/usr/local/lib:/opt/mylibs
```
```

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

### Shrink RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Remove directories from RPATH that do not contain libraries referenced by DT_NEEDED. Use --allowed-rpath-prefixes to restrict which paths are kept.

```bash
# Before: RPATH might contain build directories
patchelf --print-rpath my-program
# Output: /tmp/build-foo/.libs:/usr/local/lib:/opt/mylibs:/nonexistent/path

# Shrink RPATH to only directories containing needed libraries
patchelf --shrink-rpath my-program

# After: Only directories with actual needed libraries remain
patchelf --print-rpath my-program
# Output: /usr/local/lib:/opt/mylibs

# Shrink RPATH but only allow certain prefixes
# Useful for removing temporary build paths while keeping system paths
patchelf --shrink-rpath --allowed-rpath-prefixes /usr/lib:/opt/mylibs my-program

# This removes /tmp/build entries but keeps /usr and /opt paths
patchelf --shrink-rpath --allowed-rpath-prefixes /usr:/opt my-program
```

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

### Set SONAME for Shared Library

Source: https://context7.com/nixos/patchelf/llms.txt

Sets or modifies the DT_SONAME entry of a shared library. The SONAME is the canonical name used by the dynamic linker to identify the library at runtime.

```bash
# Print current SONAME
patchelf --print-soname libmylib.so.1.2.3
```

```bash
# Set a new SONAME
patchelf --set-soname libmylib.so.2 libmylib.so.1.2.3
```

```bash
# Create a library with proper SONAME
cp libmylib.so libmylib.so.1.0.0
patchelf --set-soname libmylib.so.1 libmylib.so.1.0.0
```

```bash
# Rename a library's SONAME for versioning
patchelf --set-soname libnewname.so.3.4.5 path/to/libmylibrary.so.1.2.3
```

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

### Executable Stack Control

Source: https://context7.com/nixos/patchelf/llms.txt

Controls the executable stack flag in the GNU_STACK program header. Clearing this flag improves security by preventing stack-based code execution attacks. Setting it is for legacy binaries that require an executable stack.

```bash
# Print current execstack status
patchelf --print-execstack my-program
```

```bash
# Clear the executable stack flag (improve security)
patchelf --clear-execstack my-program
```

```bash
# Set the executable stack flag (for legacy binaries that require it)
patchelf --set-execstack my-program
```

```bash
# Works on both executables and shared libraries
patchelf --clear-execstack libmylib.so
patchelf --print-execstack libmylib.so
```

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

### Remove Needed Library Dependency

Source: https://context7.com/nixos/patchelf/llms.txt

Removes a declared dependency on a shared library (DT_NEEDED entry). This is useful for removing unnecessary dependencies or replacing them with alternative implementations.

```bash
# Print current dependencies
patchelf --print-needed my-program
```

```bash
# Remove a specific dependency
patchelf --remove-needed libbar.so.1 my-program
```

```bash
# Remove multiple dependencies
patchelf --remove-needed libold1.so --remove-needed libold2.so my-program
```

```bash
# Verify removal
patchelf --print-needed my-program
```

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

### Remove RPATH

Source: https://context7.com/nixos/patchelf/llms.txt

Completely removes the DT_RPATH or DT_RUNPATH entry from an executable or library.

```APIDOC
## Remove RPATH

### Description
Completely removes the DT_RPATH or DT_RUNPATH entry from an executable or library, causing the dynamic linker to use only default search paths and LD_LIBRARY_PATH.

### Method
`patchelf`

### Parameters
#### Command Line Arguments
- `--print-rpath` - Prints the current RPATH.
- `--remove-rpath` - Removes the RPATH/RUNPATH entry entirely.
- `--output <output_file>` - Specifies an output file to preserve the original binary.

### Request Example
```bash
# Check current RPATH
patchelf --print-rpath my-program

# Remove RPATH entirely
patchelf --remove-rpath my-program
```

### Response Example
```
# Output of --print-rpath after removal
(empty output or no RPATH entry)
```
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.