[Original writeup.](https://github.com/StroppaFR/CTF-Writeups/blob/master/2019/Evlz-CTF-2019/Jail.md)
When connecting, we are inside a shell script that executes our commands. We can get out with **bash**.
From there we can't see the standard output stream but we can see the standard error stream so we can simply redirect with **1>&2** and find the flag.
    bash-4.3$ /bin/ls 1>&2    Desktop  Documents  Music  Pictures  Videos  bin  flag.txt  programs    bash-4.3$ /bin/ls /bin 1>&2    bash  ec.sh  echo  ls  sh    bash-4.3$ /bin/ls /usr/bin 1>&2    awk  chattr  chsh  ssh	vim  wc    bash-4.3$ /usr/bin/vim flag.txt 1>&2
> Pass: evlz{0ut_0f_ech0}ctf