The tilde in your PATH may not be your HOME

I was playing with the nono agent sandboxing tool and it greeted me with a warning: PATH entries the sandbox can write to: ~/.local/bin/ which looked suspicious. In other words, doing this in your ~/.bashrc or ~/.zshrc: export PATH="$PATH:~/.local/bin/" will not expand the ~ (tilde) into the home path (or $HOME) as the tilde to home expansion happens only in unquoted inputs, as also the bash documentation says: If a word begins with an unquoted tilde character (‘~’), all of the characters up to the first unquoted slash (…) are considered a tilde-prefix. (…) Bash checks each variable assignment for unquoted tilde-prefixes immediately following a ‘:’ or the first ‘=’, and performs tilde expansion in these cases. (…) So instead of having /home/<user>/.local/bin/ added to PATH we end up with ./~/.local/bin/ added to PATH. And to fix this, we can do this: export PATH="$PATH:$HOME/.local/bin/" Note that the unquoted version export PATH=$PATH:~/.local/bin actually works in Bash and Zsh, because tilde expansion is also performed in variable assignments after = and after each :. But relying on that is fragile as for example, a whitespace will break the variable assignment. The problem can also be seen here: $ ls -la total 0 drwxr-xr-x@ 2 dc staff 64 Oct 2 13:37 . drwxr-x---+ 105 dc staff 3360 Oct 2 13:37 .. $ mkdir -p ./~/.local/bin/ $ printf '#include <stdio.h>\nint main() { puts("hello"); }'>a.c; gcc a.c -o ./~/.local/bin/kek $ PATH="~/.local/bin/" kek hello $ tree -f . ├── ./~ │ └── ./~/.local │ └── ./~/.local/bin │ └── ./~/.local/bin/kek └── ./a.c 4 directories, 2 files As we can see, the kek binary was found and executed from ./~/.local/bin/ — the home directory was never involved. Check your PATH You can quickly check whether you have this problem with: $ echo "$PATH" | grep -- '~' or, to see each entry on its own line: $ echo "$PATH" | tr ':' '\n' | grep '~' ~/.local/bin/ If it prints anything, go fix your .bashrc/.zshrc/.profile and replace the ~ with $HOME :). Btw, kudos to the nono tool for warning about this - even though the warning could be more verbose (PR incoming).