dat2gmt: 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/dat2gmt - from package: GMT

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

On Debian possible default full paths are:

/usr/lib/gmt/bin/dat2gmt - from package: GMT

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

Error in other languages:
dat2gmt: bevel nie gevind nie
dat2gmt: comandă negăsită
dat2gmt: comando não encontrado
dat2gmt: commande introuvable
dat2gmt: command not found
dat2gmt: käsku ei ole
dat2gmt: không tìm thấy lệnh
dat2gmt: komanda nerasta
dat2gmt: Kommando nicht gefunden.
dat2gmt: kommandot finns inte
dat2gmt: komut yok
dat2gmt: nie znaleziono polecenia
dat2gmt: níor aimsíodh an t-ordú
dat2gmt: no se encontró la orden
dat2gmt: no s'ha trobat l'ordre
dat2gmt: opdracht niet gevonden
dat2gmt: parancs nem található
dat2gmt: perintah tidak ditemukan
dat2gmt: príkaz nenájdený
dat2gmt: příkaz nenalezen
dat2gmt: команда не найдена
dat2gmt: командата не е открита
dat2gmt: 命令找不到
dat2gmt: コマンドが見つかりません