ledger: 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/ledger - from package: ledger

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

On Debian possible default full paths are:

/usr/bin/ledger - from package: ledger

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

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