Running a C Program in Bash Script

Question

When I run a C program in this bash script it returns the error.

ssh -n -f *.*.*.* "cd /home/sth/remote && echo "$1" && det=$(./ossec-rootcheck)">/home/sthh/res

Error:

 ./ossec-rootcheck: No such file or directory

I want to ssh to a remote machine and then run a program on it. I know that this file is located in that path because when I edit it as you see, it works.

ssh -n -f *.*.*.* "cd /home/sth/remote && echo "$1" && ./ossec-rootcheck">/home/sthh/res

and as it echo $1 I can see that it does cd /home/sth/remote right. But I want the return value of that program to be stored in a variable,for example det.

I believe the problem is that the shell evaluates det=$(./ossec-rootcheck) before it does the cd because it is evaluating the shell parameters in the expression before it executes it. Why do you need the result in det? — lurker
– lurker, Commented Sep 17, 2013 at 12:18
The C program returns 0 or 1, if det equals 1 rest of script would do something. — Simol
– Simol, Commented Sep 17, 2013 at 12:24
You need to escape the dollar like this: det=\$(./ossec-rootcheck) so that the command runs on the remote machine. — dogbane
– dogbane, Commented Sep 17, 2013 at 12:34
@mbratch: So there's no way to get return value of a C program in bash script? I don't want what is sent to stdout. — Simol
– Simol, Commented Sep 17, 2013 at 12:36

Simol · Accepted Answer · 2013-09-17 13:07:17Z

2

ssh -n -f *.*.*.* "cd /home/sth/remote; echo "$1"; ./ossec-rootcheck || do_your_work">/home/sthh/res

You don't have to store it in a variable.

|| executes do_your_work if the exit status of ossec-rootcheck != 0

If you want to store the numeric exit status in a variable, or echo it, you can do (with proper escaping):

./ossec-rootcheck; ecode=$?; echo $ecode

edited Sep 17, 2013 at 13:07

Simol

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answered Sep 17, 2013 at 12:50

aktivb

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Comments

konsolebox · Accepted Answer · 2013-09-17 13:10:38Z

1

To get the return code or exit code of the remote code:

ssh -n -f *.*.*.* "cd /***/***/remote && echo \"$1\"; ./ossec-rootcheck; echo \$?">/home/ossl7/res

To capture errors as well:

ssh -n -f *.*.*.* "exec 2>&1; cd /***/***/remote && echo \"$1\"; ./ossec-rootcheck; echo \$?">/home/ossl7/res

Also, you probably need to omit && echo \"$1\" when you find it to be working already. And you could just use single quotes for that:

ssh -n -f *.*.*.* 'cd /***/***/remote; ./ossec-rootcheck; echo $?' >/home/ossl7/res

Or

ssh -n -f *.*.*.* 'exec 2>&1; cd /***/***/remote; ./ossec-rootcheck; echo $?' >/home/ossl7/res

answered Sep 17, 2013 at 13:10

konsolebox

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7 Comments

konsolebox Over a year ago

To store it in a variable: det=$(ssh -n -f *.*.*.* 'cd /***/***/remote; ./ossec-rootcheck; echo $?')

Simol Over a year ago

@ konsolebox:What about the stdout output of the program that I want to be stored in a file res?

konsolebox Over a year ago

If you want to copy the output, just do echo "$det" > res after that.

konsolebox Over a year ago

Also, do you mean stdout as both messages for stdout and stderr? Or just the result code?

konsolebox Over a year ago

You can redirect both your stdout and stderr to fd 2, then use fd 1 for the exit code: det=$(ssh -n -f *.*.*.* 'cd /***/***/remote; ./ossec-rootcheck >&2; echo $?' 2>/home/ossl7/res)

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