sylph-searcher: 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 Debian possible default full paths are:

/usr/bin/sylph-searcher - from package: sylph-searcher

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

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