LINK: 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:

/bin/link - from package: coreutils
/usr/lib/golang/pkg/bootstrap/bin/link - from package: golang-bin
/usr/lib64/R/bin/LINK - from package: R-core
/usr/lib/R/bin/LINK - from package: R-core

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

On Debian possible default full paths are:

/usr/lib/R/bin/LINK - from package: r-base-core
/usr/bin/link - from package: coreutils

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

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