Perl SYSTEM command fails with "Bad file descriptor" when running via Jenkins

Question

I have a simple system command to copy file from one folder to another:

my $cmd = "xcopy /Y c:\DBs\Support\db.bak c:\jenkins\workdir\sql-bak-files";

When I try to run the following system commands, all fails:

1. my $res = qx/$cmd/; 2. my $res = qx($cmd); 3. using back ticks All tries returned the error: Error number -1, error message: "Bad file descriptor".

When trying to use system($cmd) the error was Error number 65280, error message: "No such file or directory".

This perl code is running via Jenkins (ver 2.190.1) and perl v5.26.0. This problem started after migrating the code from mercurial to git, but I don't think it's related. It worked before, but now always fail :(

Re "Error number 65280, error message: "No such file or directory"", $! ("No such file or directory") is meaningless when the error isn't -1. 65280 (0xFF00) means the child ran, but returned exit code 255 (0xFF) — ikegami
– ikegami, Commented Nov 5, 2019 at 17:14
And if I have variables inside the cmd? "xcopy /Y \"$text_file\" $text_local_shared_path" ? — Shai Alon
– Shai Alon, Commented Nov 5, 2019 at 20:25

Dave Cross · Accepted Answer · 2019-11-05 15:27:33Z

3

A backslash has a special meaning in a Perl quoted string. It is used to escape the following character - to "turn off" any special meaning. If you want to use a backslash in a Perl quoted string, then you need to use another backslash to escape it.

my $cmd = 'xcopy /Y c:\\DBs\\Support\\db.bak c:\\jenkins\\workdir\\sql-bak-files';

Alternatively, Perl recognises forward slashes in Windows paths, so it might be easier to replace your code with this:

my $cmd = 'xcopy /Y c:/DBs/Support/db.bak c:/jenkins/workdir/sql-bak-files';

Note that in both cases I have replaced your double-quotes with single-quotes. This has no effect on your problem, but it seems strange to use double-quoted strings if you're not using any of their special characteristics (like the expansion of variables).

Update: To debug a problem like this, you can try printing the string.

$ perl -E'say "xcopy /Y c:\DBs\Support\db.bak c:\jenkins\workdir\sql-bak-files"'
xcopy /Y c:DBsSupportdb.bak c:jenkinsworkdirsql-bak-files

edited Nov 5, 2019 at 15:27

answered Nov 5, 2019 at 14:51

Dave Cross

69.5k3 gold badges55 silver badges101 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

ikegami Over a year ago

Re "Perl recognises forward slashes in Windows paths", Not really. Perl doesn't know anything about paths. It's Windows itself that recognizes forward slashes as a valid path separator. That said, many Windows commands require paths using / as a separator to be quoted since / normally denotes the start of a command line option. Unfortunately, that trick doesn't work with xcopy. It simply doesn't accept / as a path separator.

Shai Alon Over a year ago

And if I have variables inside the cmd? "xcopy /Y \"$text_file\" $text_local_shared_path" ?

Dave Cross Over a year ago

@ShaiAlon: Or use qq[...] instead of "..." to simplify things.

Collectives™ on Stack Overflow

Perl SYSTEM command fails with "Bad file descriptor" when running via Jenkins

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related