msp430-size: command not found

Have You tried accessing the binary with the full path?

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/msp430-size - from package: binutils-msp430

You may install the required package with command apt-get install {package}
Error in other languages:
msp430-size: bevel nie gevind nie
msp430-size: comandă negăsită
msp430-size: comando não encontrado
msp430-size: commande introuvable
msp430-size: command not found
msp430-size: käsku ei ole
msp430-size: không tìm thấy lệnh
msp430-size: komanda nerasta
msp430-size: Kommando nicht gefunden.
msp430-size: kommandot finns inte
msp430-size: komut yok
msp430-size: nie znaleziono polecenia
msp430-size: níor aimsíodh an t-ordú
msp430-size: no se encontró la orden
msp430-size: no s'ha trobat l'ordre
msp430-size: opdracht niet gevonden
msp430-size: parancs nem található
msp430-size: perintah tidak ditemukan
msp430-size: príkaz nenájdený
msp430-size: příkaz nenalezen
msp430-size: команда не найдена
msp430-size: командата не е открита
msp430-size: 命令找不到
msp430-size: コマンドが見つかりません