Shell Script that does chroot and execute commands in chroot

Question

If in shell script I write

chroot /home/mayank/chroot/codebase
cd SBC

when I run this shell script It does go in the chroot but does not execute the command cd SBC, when I exit chroot then it executes cd SBC.

How can I achieve something that does chroot and execute commands in chroot through shell script ??

try `chroot /home/whatever "COMMAND"` chroot can have command — Kent, Jul 12 '18 at 12:40
chroot /home/whatever "COMMAND" I even tried that, what actually happened was, it didn't go to chroot, but executed that "COMMAND" command successfully .. — Mayank Kataruka, Jul 12 '18 at 14:44
Moreover, I have many commands, that is to be run under chroot There must be some way ??? — Mayank Kataruka, Jul 12 '18 at 14:52
Possible duplicate of [Pass commands as input to another command (su, ssh, sh, etc)](https://stackoverflow.com/questions/37586811/pass-commands-as-input-to-another-command-su-ssh-sh-etc) — tripleee, Jul 13 '18 at 08:05

Ondrej K. · Answer 1 · 2018-07-12T20:17:52.383

18

When you run chroot without telling it what to do, it will try to start chrooted interactive shell session. So your script would "pause" at that point and when you are done with that interactive shell session, it continues out of chroot again.

One of the quick and dirt options would be to abuse here-document, like this:

chroot /home/mayank/chroot/codebase /bin/bash <<"EOT"
cd /tmp/so
ls -l
echo $$
EOT

Which takes all lines up to EOT and feeds them into bash started through chroot. Those double quotes around "EOT" should ensure bash passes the content not trying to expand variables and such. Hence that echo $$ should be PID of the inner chrooted bash.

edited Jul 12 '18 at 20:17

answered Jul 12 '18 at 18:19

Ondrej K.

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Thereis exist way to expand some variables? – Andrey Reeshkov Dec 01 '20 at 07:18
2

@AndreyReeshkov You can use `< – Ondrej K. Jan 06 '21 at 15:29
Nice post! I also have the same problem and I also found another way with python interaction, FYI. https://stackoverflow.com/questions/9673730/interacting-with-bash-from-python – kyc1109 Mar 31 '22 at 02:58

score 3 · Answer 2 · answered Jul 13 '18 at 07:06

somewhat I found a solution,

chroot /work3/tmp_GU/$build_env/sbcbuild/chroot ./test.sh

after chroot giving a script there is working fine for me.

test.sh present in the chroot folder. All commands in test.sh will be executed in chroot folder.

So basically giving a command after chroot

man chroot

chroot [OPTION] NEWROOT [COMMAND [ARG]...]

Shell Script that does chroot and execute commands in chroot

2 Answers2

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