ewfacquire: 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/ewfacquire - from package: ewftools

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

On Debian possible default full paths are:

/usr/bin/ewfacquire - from package: ewf-tools

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

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