ewfverify: 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/ewfverify - from package: ewftools

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

On Debian possible default full paths are:

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

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

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