glacier-list-duplicates: command not found

Have You tried accessing the binary with the full path?

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/glacier-list-duplicates - from package: glacier-cli

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