peardev: 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/peardev - from package: php54w-pear
/usr/bin/peardev - from package: php55w-pear
/usr/bin/peardev - from package: php56w-pear
/usr/bin/peardev - from package: php70w-pear
/usr/bin/peardev - from package: php-pear

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

On Debian possible default full paths are:

/usr/bin/peardev - from package: php-pear

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

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