onionshare-gui: 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/onionshare-gui - from package: onionshare

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

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