showseq: 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/showseq - from package: emboss

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

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