sim_mira: 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/sim_mira - from package: similarity-tester

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