transmission-show: 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/transmission-show - from package: transmission-common

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

On Debian possible default full paths are:

/usr/bin/transmission-show - from package: transmission-cli

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

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