Fastest way to concatenate files I've got 10k+ files totaling over 20GB that I need to concatenate into one file. Is there a faster way than cat input_file* >> out ? The preferred way would be a bash command, Python is acceptable too if not considerably slower.

Nope, cat is surely the best way to do this. Why use python when there is a program already written in C for this purpose? However, you might want to consider using `xargs` in case the command line length exceeds `ARG_MAX` and you need more than one `cat`. Using GNU tools, this is equivalent to what you already have:


find . -maxdepth 1 -type f -name 'input_file*' -print0 |
sort -z |
xargs -0 cat -- >>out