[FIXED] What does this "-u" do after python?

Issue

python -u -m torch.distributed.launch --nproc_per_node=1 --master_port=9421 \ Genie_Finetune.py \ --checkpoint_path="/save/delibot" \ --model_channels 128 --in_channel 128 --out_channel 128 --vocab_size 30522 \ --config_name="bert-base-uncased" --token_emb_type="random" --model_arch="s2s_CAT" \ --diffusion_steps 2000 --predict_xstart --noise_schedule="sqrt" --training_mode="s2s" \ --schedule_sampler="loss-second-moment" --tgt_max_len 64 --src_max_len 512 --data_name="deli_data_small" \ --data_path="data" \ --lr_anneal_steps 120000 --batch_size 64 --lr 5e-05 --warmup_steps 7200 --train_type="S2S_Diffusion" \ --eval_interval 200 --log_interval 200 --save_interva 20000 \ --pretrain_model_path="/save/GENIE_ckpt-500w"

Greetings, I understand this '-m' is for multiprocess, but what does this '-u' do? In addition, how do I search for the exact string '-u' in search engine? It seems like every search engine is ignoring this.

Thanks

I just don't want to delete it and causing unknown problems

Solution

The -u option in the Python command line stands for "unbuffered". When you run a Python script, by default, the standard output and standard error streams are buffered (meaning that they collect a certain amount of data before actually writing it out to the terminal or a file). This can sometimes cause delays in seeing output, especially when running Python scripts in certain environments like Docker containers, or when piping output through other commands.

When you use the -u flag, it forces the Python interpreter to run in unbuffered mode. This means that output is written immediately to the terminal or file, which can be useful for logging or when you want to see output in real-time.

As for searching for -u in a search engine, it can indeed be tricky, as search engines often ignore punctuation and special characters. A good approach is to include additional context in your search query. For instance, you could search for "python command line option -u" or "python -u flag meaning". This way, the search engine can use the surrounding context to understand that -u is a significant part of your query.

Regarding removing the -u flag, it's generally safe to do so. The impact of removing it would primarily be on how output buffering is handled. If you're not facing any issues related to delayed output or logging, then your script should run just fine without the -u flag. However, if the script was provided with this flag by someone else (like in a setup guide or a pre-written script), it's usually best to leave it as is, unless you have a specific reason to remove it.

Answered By - Kamil