gshhg: 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/gshhg - 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/gshhg - from package: GMT

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

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