gdalinfo: 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/gdalinfo - from package: gdal

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

On Debian possible default full paths are:

/usr/bin/gdalinfo - from package: gdal-bin

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

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