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