dipy_sh_estimate: 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 Debian possible default full paths are:

/usr/bin/dipy_sh_estimate - from package: python-dipy

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

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