# zlib-flate > Raw zlib compression and decompression program. > Part of `qpdf`. > More information: . - Compress a file: `zlib-flate < {{path/to/input_file}} -compress > {{path/to/compressed.zlib}}` - Uncompress a file: `zlib-flate < {{path/to/compressed.zlib}} -uncompress > {{path/to/output_file}}` - Compress a file with a specified compression level. 0=Fastest (Worst), 9=Slowest (Best): `zlib-flate < {{path/to/input_file}} -compress={{compression_level}} > {{path/to/compressed.zlib}}`