digikam: 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/digikam - from package: digikam

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

On Debian possible default full paths are:

/usr/bin/digikam - from package: digikam

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

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