tabs: 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/tabs - from package: ncurses

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

On Debian possible default full paths are:

/usr/bin/tabs - from package: ncurses-bin

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

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