asciinema: 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/asciinema - from package: asciinema

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

On Debian possible default full paths are:

/usr/bin/asciinema - from package: asciinema

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

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