seqalign: 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/seqalign - from package: embassy-domalign

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

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