acyclic: command not found

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 CentOS possible default full paths are:

/usr/bin/acyclic - from package: graphviz

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/acyclic - from package: graphviz

You may install the required package with command apt-get install {package}

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