relion_autopick: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/relion_autopick - from package: relion-bin+gui
/usr/bin/relion_autopick - from package: relion-bin+mpi+gui
/usr/bin/relion_autopick - from package: relion-bin+mpi
/usr/bin/relion_autopick - from package: relion-bin

You may install the required package with command apt-get install {package}
Error in other languages:
relion_autopick: bevel nie gevind nie
relion_autopick: comandă negăsită
relion_autopick: comando não encontrado
relion_autopick: commande introuvable
relion_autopick: command not found
relion_autopick: käsku ei ole
relion_autopick: không tìm thấy lệnh
relion_autopick: komanda nerasta
relion_autopick: Kommando nicht gefunden.
relion_autopick: kommandot finns inte
relion_autopick: komut yok
relion_autopick: nie znaleziono polecenia
relion_autopick: níor aimsíodh an t-ordú
relion_autopick: no se encontró la orden
relion_autopick: no s'ha trobat l'ordre
relion_autopick: opdracht niet gevonden
relion_autopick: parancs nem található
relion_autopick: perintah tidak ditemukan
relion_autopick: príkaz nenájdený
relion_autopick: příkaz nenalezen
relion_autopick: команда не найдена
relion_autopick: командата не е открита
relion_autopick: 命令找不到
relion_autopick: コマンドが見つかりません