mercurial-convert-repo: 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/mercurial-convert-repo - from package: mercurial

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

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