revcomp: 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/revcomp - from package: biosquid

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

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