Basically, is there some kind of analogue of exit(-1) function in GNU Smalltalk 3.2.5? Or is there a way to configure it so that if it encounters an error during execution it'd return non-zero exit code? I want to be able to detect if gst executed the st code file successfully or if an error (syntax or runtime/exception) occurred.
Yes, it is possible using ObjectMemory quit: 0 or ObjectMemory quit: 1 etc. The source code for ObjectMemory quit:
ObjectMemory class >> quit: exitStatus [
"Quit the Smalltalk environment, passing the exitStatus integer
to the OS. Files are closed and other similar cleanups occur."
<category: 'builtins'>
<primitive: VMpr_ObjectMemory_quit>
SystemExceptions.WrongClass signalOn: exitStatus mustBe: SmallInteger
]
Searching for 'quit' in the source code will provide examples of it in action.
I want to use the pidof by a process given by name in tcl. I have used [exec pidof $proc_name ], but it always returns an error: child process exited abnormally.
I read somewhere exec always treat non-zero return as error as pidof return the process id number. Does anyone know if there is a workaround? Thanks in advance!
I want to use pidof is that i want to see if that process is running if not i will restart the process.
The problem is that pidof does strange things with exit codes:
Exit Status
At least one program was found with the requested name.
No program was found with the requested name.
This interacts badly with exec which treats a non-zero exit code as indicating that it should tell the rest of Tcl that there was an error.
The simplest way of dealing with this is a little extra shell script wrapper. Let's hide it inside a procedure for convenience:
proc pidof {name} {
exec /bin/bash -c "pidof '$name'; exit \$(( \$? - 1 ))"
}
All that does is subtract 1 from the exit code before it hits back into Tcl.
(You could also fix this using the techniques described in the exec manual but I think it's simpler to fix on the bash side this time.)
I ran into this and ended up causing some issues with the old linux environment I run in (no bash and exit code handling was a bit different with busybox).
My solution that should work anywhere would be similar to what a few suggested:
proc pidof {name} {
catch {exec -ignorestderr -- pidof $name} pid
if {[string is entier -strict $pid]} {
return $pid
}
}
I am looking for a complete list of all possible jvm exit codes (not java System.exit(x)). The only thing I could find by using a search engine is a list of SIGTERM exit codes: http://journal.thobe.org/2013/02/jvms-and-kill-signals.html . I want to know if there are specific exit codes for uncatched Exceptions?
Argument passed to System.exit(x) -> becomes the JVM exit code.
Exit code 0 is used to indicate normal exit.
Unique positive exit code to indicate specific problem.
I want to know if there are specific exit codes for uncatched
Exceptions?
No. If all non-daemon threads exit normally(presence/absence of exception does not matter), JVM terminates with 0.
Exit code between 1 and 127 are specific codes used to indicate error in JVM. e.g. mismatched jdk/jre versions, incorrect memory configuration/command-line options, etc.
About the link
http://journal.thobe.org/2013/02/jvms-and-kill-signals.html
JVM exit due to specific signal would be
128+signal-id
List of signal-id can be found using kill -l
In a DOS batch script, I'm running a single command on a remote (also windows) computer using plink. Formerly, this command was only run on the local machine, and was relying on the return code to determine success. Is there a way to easily get this information back through plink?
That's not possible with plink. The current consensus is to have the remote script echo its exit code to a log file, then use pscp to transfer the log file to the local machine.
See http://fixunix.com/ssh/74235-errorlevel-capturing-plink.html.
with plink 0.66
C:\Code>echo Y | "C:\Program Files (x86)\PuTTY\plink.exe" bob#myserver exit 42
C:\Code>echo %ERRORLEVEL%
42
Also for #John Wiersba's concern about when a connection cannot be made, this appears to be fixed
C:\CodeMisc>echo Y | "C:\Program Files (x86)\PuTTY\plink.exe" bob#garbageservername exit 42
Unable to open connection:
Host does not exist
C:\Code>echo %ERRORLEVEL%
1
Also note the piping of echo Y ... this enables you to accept the server fingerprint automatically (a little dangerous to say the least ... but our login server is load balanced, so you are always getting different fingerprints :( )
However as #LeonBloy notes, plink still has some connection conditions which return a zero exit code. If you know your exit code range and you don't have a good way of communicating back to windows via a file. You could either +3 to the exit code (if you know the exit code will never == 253-255) or you could apply a bitwise OR (I'd suggest exit $(($?|128)) - in bash).
Or if you don't care about the exact exit code, you could return 2 for success, and zero for failure. Thus a non-two exit code would indicate failure. In bash this would be: echo $((($?==0) << 1)). This would be by far the most robust general purpose solution, but you should make sure your exit code is logged for debug-ability.
What is the meaning of return value 127 from $? in UNIX.
Value 127 is returned by /bin/sh when the given command is not found within your PATH system variable and it is not a built-in shell command. In other words, the system doesn't understand your command, because it doesn't know where to find the binary you're trying to call.
Generally it means:
127 - command not found
but it can also mean that the command is found,
but a library that is required by the command is NOT found.
127 - command not found
example: $caat
The error message will
bash:
caat: command not found
now you check using echo $?
A shell convention is that a successful executable should exit with the value 0. Anything else can be interpreted as a failure of some sort, on part of bash or the executable you that just ran. See also $PIPESTATUS and the EXIT STATUS section of the bash man page:
For the shell’s purposes, a command which exits with a zero exit status has succeeded. An exit status
of zero indicates success. A non-zero exit status indicates failure. When a command terminates on a
fatal signal N, bash uses the value of 128+N as the exit status.
If a command is not found, the child process created to execute it returns a status of 127. If a com-
mand is found but is not executable, the return status is 126.
If a command fails because of an error during expansion or redirection, the exit status is greater than
zero.
Shell builtin commands return a status of 0 (true) if successful, and non-zero (false) if an error
occurs while they execute. All builtins return an exit status of 2 to indicate incorrect usage.
Bash itself returns the exit status of the last command executed, unless a syntax error occurs, in
which case it exits with a non-zero value. See also the exit builtin command below.
It has no special meaning, other than that the last process to exit did so with an exit status of 127.
However, it is also used by bash (assuming you're using bash as a shell) to tell you that the command you tried to execute couldn't be executed (i.e. it couldn't be found). It's unfortunately not immediately deducible though, if the process exited with status 127, or if it couldn't found.
EDIT:
Not immediately deducible, except for the output on the console, but this is stack overflow, so I assume you're doing this in a script.
If you're trying to run a program using a scripting language, you may need to include the full path of the scripting language and the file to execute. For example:
exec('/usr/local/bin/node /usr/local/lib/node_modules/uglifycss/uglifycss in.css > out.css');
This error is also at times deceiving. It says file is not found even though the files is indeed present. It could be because of invalid unreadable special characters present in the files that could be caused by the editor you are using. This link might help you in such cases.
-bash: ./my_script: /bin/bash^M: bad interpreter: No such file or directory
The best way to find out if it is this issue is to simple place an echo statement in the entire file and verify if the same error is thrown.
If the IBM mainframe JCL has some extra characters or numbers at the end of the name of unix script being called then it can throw such error.
In addition to the given answers, note that running a script file with incorrect end-of-line characters could also result in 127 exit code if you use /bin/sh as your shell.
As an example, if you run a shell script with CRLF end-of-line characters in a UNIX-based system and in the /bin/sh shell, it is possible to encounter some errors like the following I've got after running my script named my_test.sh :
$ ./my_test.sh
sh: 2: ./my_test.sh: not found
$ echo $?
127
As a note, using /bin/bash, I got 126 exit code, which is in accordance with gnu.org documentation about the bash :
If a command is not found, the child process created to execute it returns a status of 127. If a command is found but is not executable, the return status is 126.
Finally, here is the result of running my script in /bin/bash :
arman#Debian-1100:~$ ./my_test.sh
-bash: ./my_test.sh: /bin/bash^M: bad interpreter: No such file or directory
arman#Debian-1100:~$ echo $?
126
go to C:\Program Files\Git\etc
open gitconfig with notepad
change
[core]
autocrlf = true
To
[core]
autocrlf = false