tomcat-digest: 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/tomcat-digest - from package: tomcat

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

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