Linux – Bash on Ubuntu on Windows gives error “-bash: /home/user/.bashrc: Permission denied” on startup

In order to read /etc/bash.bashrc (and /etc/password) the permissions on the parent directories matter, too. In particular, you need +x on them. In your case (from the chat conversation) it turns out somehow the permissions on /etc were wrong.

The inability to read /etc/passwd is why bash and whoami can't find your username.

Debian's default for /etc is 0755; so chmod 0755 /etc (as root) will fix at least that immediate problem. You should also investigate how that happened, to determine if there might be other directories with incorrect permissions.

You need to convert the line endings of /mnt/c/Users/Philipp/.aliases_win from windows format (CRLF) to unix format (LF). You can do this with sed (this will overwrite the file):

sed -i 's/\r$//' /mnt/c/Users/Philipp/.aliases_win

Explanation:

The reason bash says : command not found is because it interprets the carriage return on the "blank" lines in your windows-formatted file as the name of a command. You can test this for yourself in the bash shell by typing CTRL-V, CTRL-M and then hitting enter (CTRL-M or ^M corresponds to a carriage return, see man console_codes).

Once you removed all the blank lines, you were left with just a few alias commands, which gave you : File or directory not found after executing the aliases because the carriage return on the end of the alias lines was actually added into the alias. For example, the line alias ..='cd ..'<CR><LF> made .. an alias for cd ..<CR>, which does not go to the parent folder .. but instead tries to change to the directory with the name ..<CR>. The error message when running this alias doesn't start with the typical bash: cd: foldername because echoing the carriage return in the folder name causes the cursor to return to the beginning of the line; try something like echo aaaa<CR>bb to see this more clearly.