wgsim: command not found

Have You tried accessing the binary with the full path?

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/wgsim - from package: samtools

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