psi-cd-hit-2d-g1: 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
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

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/psi-cd-hit-2d-g1 - from package: cd-hit

You may install the required package with command apt-get install {package}
Error in other languages:
psi-cd-hit-2d-g1: bevel nie gevind nie
psi-cd-hit-2d-g1: comandă negăsită
psi-cd-hit-2d-g1: comando não encontrado
psi-cd-hit-2d-g1: commande introuvable
psi-cd-hit-2d-g1: command not found
psi-cd-hit-2d-g1: käsku ei ole
psi-cd-hit-2d-g1: không tìm thấy lệnh
psi-cd-hit-2d-g1: komanda nerasta
psi-cd-hit-2d-g1: Kommando nicht gefunden.
psi-cd-hit-2d-g1: kommandot finns inte
psi-cd-hit-2d-g1: komut yok
psi-cd-hit-2d-g1: nie znaleziono polecenia
psi-cd-hit-2d-g1: níor aimsíodh an t-ordú
psi-cd-hit-2d-g1: no se encontró la orden
psi-cd-hit-2d-g1: no s'ha trobat l'ordre
psi-cd-hit-2d-g1: opdracht niet gevonden
psi-cd-hit-2d-g1: parancs nem található
psi-cd-hit-2d-g1: perintah tidak ditemukan
psi-cd-hit-2d-g1: príkaz nenájdený
psi-cd-hit-2d-g1: příkaz nenalezen
psi-cd-hit-2d-g1: команда не найдена
psi-cd-hit-2d-g1: командата не е открита
psi-cd-hit-2d-g1: 命令找不到
psi-cd-hit-2d-g1: コマンドが見つかりません