Does ipython have a setting similar to '-e' in bash that stops the execution of the script if any ipython's shell command returns a non-zero value?
Not directly, no. However, after a !foo shell command, the exit code is stored as the value _exit_code. So your script could check that and throw an error.
For some reason, on my system it multiplies all the exit codes by 256. I'm not at all sure why it's doing that.
Related
What's the Windows batch file equivalent of set -o errexit in a bash script?
I have a long batch file filled with different programs to run on Windows command line... basically its an unrolled make file with every compiler command that needs to be run to build an exe in a long sequence of commands.
The problem with this method is that I want it to exit the batch command on the first non-zero return code generate by a command in the script.
As far as I know, Windows batch files have a problem where they don't automatically exit on the first error without adding a lot of repetitive boilerplate code between each command to check for a non-zero return code and to exit the script.
What I'm wondering about, is there an option similar to bash's set -o errexit for Windows cmd.exe? or perhaps a technique that works to eliminate too much boilerplate error checking code... like you set it up once and then it automatically exits if a command returns a non-zero return code without adding a bunch of junk to your script to do this for you.
(I would accept PowerShell option as well instead of cmd.exe, except PowerShell isn't very nice with old-unix-style command flags like: -dontbreak -y ... breaking those commands without adding junk to your command line like quotes or escape characters... not really something I want to mess around with either...)
CMD/Batch
As Ken mentioned in the comments, CMD does not have an equivalent to the bash option -e (or the equivalent -o errexit). You'd have to check the exit status of each command, which is stored in the variable %errorlevel% (equivalent to $? in bash). Something like
if %errorlevel% neq 0 then exit /b %errorlevel%
PowerShell
PowerShell already automatically terminates script execution on errors in most cases. However, there are two error classes in PowerShell: terminating and non-terminating. The latter just displays an error without terminating script execution. The behavior can be controlled via the variable $ErrorActionPreference:
$ErrorActionPreference = 'Stop': terminate on all errors (terminating and non-terminating)
$ErrorActionPreference = 'Continue' (default): terminate on terminating errors, continue on non-terminating errors
$ErrorActionPreference = 'SilentlyContinue': don't terminate on any error
PowerShell also allows more fine-grained error handling via try/catch statements:
try {
# run command here
} catch [System.SomeException] {
# handle exception of a specific type
} catch [System.OtherException] {
# handle exception of a different type
} catch {
# handle all other exceptions
} finally {
# cleanup statements that are run regardless of whether or not
# an exception was thrown
}
I have a confusion over the exit code of the application and the bash return value. For an eclipse application, a command line interface ran using eclipse returns the exit code as 1 (which is expected upon error). but when I run same command line using shell file and checks the return value with "echo $?" it always returns value as 0.
Application launched in command line mode in Eclipse :
Shell script :
command ="toolCli.exe -application arguments"
$command
echo $?
Output I get here is always 0, what's exactly the difference here?
$ com="echoo hi"
$ $com
No command 'echoo' found, did you mean:
Command 'echo' from package 'coreutils' (main)
echoo: command not found
$ echo $?
127
As you can see the exit value does work, I believe your issue might be to do with the environment, as in the eclipse environment be different from your bash environment?
From the java path, it looks like you have a 64 bit windows env and that eclipse might be using the standard windows command line, so I'm interested in how you are expecting it to behave as a bash env?
So maybe run the command under a windows command line and see if it fails, compare the java setup in both environments.
I am on a sun ultra10 running solaris. I'm trying to alter a bourne shell script so that it will close the window (a cmdtool). Ive tried exit, exit -0, exit -1, system(exit), system("exit").
the script always just exits with the cmdtool still open.
As far as I know, this is not possible. A workaround would be not to alter the script, but how it is called:
./script && exit
This will close the shell window after the script has finished execution with return value 0. It may make sense to leave the window open if the script returned with an error, so that any error messages are preserved. If you want the window to close either way, just use a ; instead of the &&.
I have a perl script (verifyCopy.pl) that uses system() to call a shell script (intercp.sh).
From inside the shell script, I have set up several exit's with specific exit codes and I'd like to be able to do different things based on which exit code is returned.
I've tried using $?, I have tried assigning the value of system("./intercp.sh") to a variable then checking the value of that, but the error message is always 0.
Is this because even though something inside the shell script fails, the actual script succeeds in running?
I tried adding a trap in the shell script (ie trap testexit EXIT and testexit() { exit 222; } but that didn't work either.
$? should catch the exit code from your shell script.
$ cat /tmp/test.sh
#!/bin/sh
exit 2
$ perl -E 'system("/tmp/test.sh"); say $?'
512
Remember that $? is encoded in the traditional manner, so $? >> 8 gives the exit code, $? & 0x7F gives the signal, and $? & 0x80 is true if core was dumped. See perlvar for details.
Your problem may be one of several things: maybe your shell script isn't actually exiting with the exit code (maybe you want set -e); maybe you have a signal handle for SIGCHLD eating the exit code; etc. Try testing with the extremely simple shell script above to see if its a problem in your perl script or your shell script.
If I run a Perl script from a command prompt (c:\windows\system32\cmd.exe), how can I exit the command prompt after the script finishes executing.
I tried system("exit 0") inside the Perl script but that doesn't exit the cmd prompt shell from where the Perl script is running.
I also tried exit; command in the Perl script, but that doesn't work either.
Try to run the Perl script with a command line like this:
perl script.pl & exit
The ampersand will start the second command after the first one has finished. You can also use && to execute the second command only if the first succeeded (error code is 0).
Have you tried cmd.exe /C perl yourscript.pl ?
According to cmd.exe /? /C carries out the command specified by string and then terminates.
If you're starting the command shell just to run the perl script, the answer by Arkaitz Jimenez should work (I voted for it.)
If not, you can create a batch file like runmyscript.bat, with content:
#echo off
perl myscript.pl
exit
The exit will end the shell session (and as a side effect, end the batch script itself.)
You can start the program in a new window using the START Dos command. If you call that with /B then no additional window is created. Then you can call EXIT to close the current window.
Would that do the trick?
You can send a signal to the parent shell from Perl:
kill(9,$PARENT_PID);`
Unfortunately, the getppid() function is not implemented in Perl on windows so you'll have to find out the parent shell PID via some other means. Also, signal #9 might not be the best choice.