Space not taken as an argument separator by shell script (could someone please explain that small file difference ?)

**SHORT VERSION (TL;DR)** I have 2 small one-line files, ***seemingly*** identical : $ cat f1 f2 ./cconv.sh 100 EUR USD ./cconv.sh 100 EUR USD But they are not, there is a 1 byte difference in size : $ ls -l f1 f2 (...) 24 oct. 30 16:19 f1 (...) 23 oct. 30 16:19 f2 $ diff f1 f2 1c1 ./cconv.sh 100 EUR USD I used dhex to figure out the hexadecimal difference. It appears that : - f1 finishes with c2 a0 55 53 44 0a - f2 finishes with 20 55 53 44 0a Does anybody have a clue what's going on here ? What's the difference, and more importantly, where could it come from ? Here is a link to a zip file containing the 2 files, and a screenshot of the dhex result. **LONG VERSION (ADDITIONAL EXPLANATIONS)** The 2 files are excerpts from my ~/.bash_history file. I noticed a very strange behavior from my shells. Take the following very basic script : #!/bin/sh echo $# echo "$1" echo "$2" echo "$3" exit 0 Under certain circumstance (but which ones ???), it doesn't take the space as an argument separator : $ ./cconv.sh 100 EUR USD 2 100 EUR USD But sometimes it works just as it is supposed to : $ ./cconv.sh 100 EUR USD 3 100 EUR USD It drives me nuts ! I spent several hours trying to figure out what's going on. Here are some tests I did to try and narrow it down : - I work on a laptop with Debian 11, Gnome 3.38. But I happen to also have a virtual machine with exactly the same OS (D11, G3.38), and in the VM everything works just fine. So obviously I must have done something to my bare metal laptop for it to misbehave. But what ??? - I noticed that the problem only occurs in a graphical session. If I open a tty (Ctrl+Alt+F*n*), it works fine - I suspected my terminal emulator. But the behavior is the same in different emulators (I tried Gnome Terminal, Terminator and Konsole, same result) - I suspected the shell. But the behavior is the same either with Bash or Dash - I disabled all customization I could think of : - I temporarily removed /etc/bashrc, /etc/profile, /etc/inputrc and /etc/rc.local - I temporarily removed ~/.bashrc, ~/.profile and ~/.inputrc - I disabled all Gnome Shell's extensions - I even suspected the keyboard, and plugged in a USB keyboard. Same result. I'm really confused, and have not a clue what's going on. I finally noticed that small difference between the 2 commands in ~/.bash_history : one comes from my Gnome session, the other comes from my tty session. Obviously there's a difference, but what is it exactly, and what could be the cause ?