Bash script in background - bash

i'm trying to create a simple script for ARM cross compiler toolchain. When i try to debug with
#!/bin/bash
read VAR
echo `qemu-arm -g $VAR file &`
I should get a output like "[13] 22189", in this way i can use the other command:
gdb-multiarch -q --nh -ex 'set architecture arm' -ex 'file fileName' -ex ' target remote localhost:$VAR"
but i don't get any output. I'm not a expert about bash script but this script can help me so much because commands aren't easy to remember. If someone can help me, i would appreciate so much

Related

Allow user input in second command in bash pipe

I'm looking for how I might allow user input in a second command in a bash statement and I'm not sure how to go about it. I'd like to be able to provide a one-liner for someone to be able to install my application, but part of that application process requires asking some questions.
The current script setup looks like:
curl <url/to/bootstrap.sh> | bash
and then boostrap.sh does:
if [ $UID -ne 0 ]; then
echo "This script requires root to run. Restarting the script under root."
exec sudo $0 "$#"
exit $?
fi
git clone <url_to_repo> /usr/local/repo/
bash /usr/local/repo/.setup/install_system.sh
which in turn calls a python3 script that asks for input.
I know that the the curl in the first line is using stdin and so that might make what I'm asking impossible and that it has to be two lines to ever work:
wget <url/to/boostrap.sh>
bash bootstrap.sh
You can restructure your script to run this way:
bash -c "$(curl -s http://0.0.0.0//test.bash 2>/dev/null)"
foo
wololo:a
a
My test.bash is really just
#!/bin/bash
echo foo
python -c 'x = raw_input("wololo:");print(x)'`
To demonstrate that stdin can be read from in this way. Sure it creates a subshell to take care of curl but it allows you to keep reading from stdin as well.

Connecting to SSH using a bash script

I am trying to write a bash script to make things faster. Is it not possible to connect to the server with the code below in a bash script? I can't make it work, even though it works in the terminal.
#!/bin/bash -x
echo "Starting connection script"
sh -i /home/EC2_KEY_HEHE.pem ubuntu#ec2-IP.blabla.amazonaws.com
What I get when I run is a not found output for each line in the pem file,
$ /home/EC2_KEY_HEHE.pem: 1: /home/EC2_KEY_HEHE.pem: -----BEGIN: not found
$ /home/EC2_KEY_HEHE.pem: 1: /home/EC2_KEY_HEHE.pem: adsnaleAFemasdsdsdnds: not foundMadfdasfdasfnda;vonraada
...
Some debug is needed.
Please change:
ssh -i /home/EC2_KEY_HEHE.pem ubuntu#ec2-IP.blabla.amazonaws.com
to:
#!/bin/bash -x
echo "Starting connection script"
ssh -vi /home/EC2_KEY_HEHE.pem ubuntu#ec2-IP.blabla.amazonaws.com
does it produce an idea about the reason ?
you are calling sh which is kind of shell change it to ssh

BASH get error code in parent terminal from child terminal?

In a bash script I start a new terminal with a command that gives an error. However I don't seem to be able to grab that error code:
#! /bin/bash
gnome-terminal -x bash -c "cat dksdamfasdlm"
echo $?
Output:
0
So I get the error code of the gnome-terminal command instead of the cat one. One suggestion I got, was to make a file with the code and read that from the parent bash. The problem is that I still seem to not be able and read the error code even that way:
#! /bin/bash
gnome-terminal -x bash -c "cat dksdamfasdlm; echo $?; sleep 2"
Output (on new terminal):
cat: dksdamfasdlm: No such file or directory
0
Why is that? Some suggestion on how to solve this? I just want to somehow grab the error in the new terminal from the parent bash.
It seems GNOME Terminal exits immediately after starting, which is obvious if you run for example gnome-terminal -x sleep 10. Since it doesn't wait for the command to finish, there's no way the return code will be that of the command. I could find no option in gnome-terminal --help-all to keep the process in the foreground.
Regarding your second question, you've double-quoted the command, so $? is expanded before running it. This should work:
gnome-terminal -x bash -c 'cat dksdamfasdlm; echo $?; sleep 2'
PS: The -x option is not documented in GNOME Terminal 3.8.4's gnome-terminal --help-all, various references don't help much, and there's no good explanation for why there's a -e option with identical semantics and different syntax.

How I can write a command in a terminal which is running a program and I open from a script

I already know how to open a terminal in a bash with gnome-terminal and execute a program:
gnome-terminal -e ./OpenBTSCLI
But I also need that once open that program in the new terminal, write another command inside.
When a I tried to use echo, the message appear in the terminal where I run the bash.
I tried: gnome-terminal -e "bash -c './OpenBTSCLI && echo message'" that I find online but its not working, it only do the first part.
Anyone have an idea of how to resolve this? Thank you
I think it does the second command as well, but the new terminal closes as soon as the command's finished, so you don't see it. I reversed the order of quotes and added a 1s sleep at the end to allow seeing the echo.
gnome-terminal -e 'bash -c "./OpenBTSCLI && echo message && sleep 1"'

How to view the command executed in a script as it is executed?

I have a bash script I've written to automate something tedious, so I got the command looking right in echo, but when I run it, it doesn't work. This is what I'm doing:
CMD='custom_script update --flag=value --comment="testing"'
echo -e "Running $CMD"
$CMD
The echo shows:
custom_script update --flag=value --comment="testing"
which is correct, but that is not what is actually run with the $CMD line (I know because if I copy and paste the output from echo, it works, but the error message after running in the script suggests the quoting is off).
I think I can figure this out if I can see the command run by $CMD, but I don't know how to do that.
Run it like
bash -x script.sh
or modify the shebang like
#!/bin/bash -x
Looks like
eval $CMD
is what I needed.

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