# pv > Monitor the progress of data through a pipe. > More information: . - Print the contents of the file and display a progress bar: `pv {{path/to/file}}` - Measure the speed and amount of data flow between pipes (`--size` is optional): `command1 | pv --size {{expected_amount_of_data_for_eta}} | command2` - Filter a file, see both progress and amount of output data: `pv -cN in {{big_text_file}} | grep {{pattern}} | pv -cN out > {{filtered_file}}` - Attach to an already running process and see its file reading progress: `pv -d {{PID}}` - Read an erroneous file, skip errors as `dd conv=sync,noerror` would: `pv -EE {{path/to/faulty_media}} > image.img` - Stop reading after reading specified amount of data, rate limit to 1K/s: `pv -L 1K --stop-at --size {{maximum_file_size_to_be_read}}`