tesseract: 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/tesseract - from package: tesseract

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

On Debian possible default full paths are:

/usr/bin/tesseract - from package: tesseract-ocr

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

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