Bash dá sugestões quando comandos desconhecidos são inseridos.
$ apr
No command 'apr' found, did you mean:
Command 'arp' from package 'net-tools' (main)
Command 'apm' from package 'apmd' (main)
Command 'apf' from package 'apf-firewall' (universe)
Command 'apg' from package 'apg' (main)
Command 'pr' from package 'coreutils' (main)
Command 'gpr' from package 'gpr' (universe)
Command 'ar' from package 'binutils' (main)
Command 'ar' from package 'binutils-multiarch' (universe)
Command 'par' from package 'par' (universe)
Command 'lpr' from package 'lpr' (universe)
Command 'lpr' from package 'lprng' (universe)
Command 'lpr' from package 'gnuspool' (universe)
Command 'lpr' from package 'cups-bsd' (main)
apr: command not found
Se houver duas possibilidades, o bash apenas informa quantos são. Na verdade, não é muito útil.