libreoffice: 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/libreoffice - from package: libreoffice-core

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

On Debian possible default full paths are:

/usr/bin/libreoffice - from package: libreoffice-common

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

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