ikiwiki-calendar: 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/ikiwiki-calendar - from package: ikiwiki

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

On Debian possible default full paths are:

/usr/bin/ikiwiki-calendar - from package: ikiwiki

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

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