v.univar: command not found

Have You tried accessing the binary with the full path?

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/lib64/grass-6.4.4/bin/v.univar - from package: grass

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

On Debian possible default full paths are:

/usr/lib/grass64/bin/v.univar - from package: grass-core

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