pycallgraph: 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/pycallgraph - from package: python-pycallgraph

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

On Debian possible default full paths are:

/usr/bin/pycallgraph - from package: python-pycallgraph

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

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