Execute command with spaces in perl

naveenp5 has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Execute command with spaces in perl by Corion (Patriarch) on Aug 27, 2018 at 10:22 UTC
Your quoting does not match how the Windows shell (`cmd.exe`) processes quotes. `cmd.exe` does not recognize a backslash before a space as the intention to quote that space. A working invocation of `firefox.exe` could be: `my $ff_exe = q{C:\\Program Files\\Mozilla Firefox\\firefox.exe}; my @cmd = ($ff_exe, '--version'); my $shell_command = join " ", # separate by spaces map { /\s/ ? qq{"$_"} : $_ } # enclose in double q +uotes if needed @cmd; print $shell_command;` [download] Note that under Windows, the `--version` command line switch does not output anything.	[reply] [d/l] [select]
Re^2: Execute command with spaces in perl by pryrt (Abbot) on Aug 27, 2018 at 15:52 UTC
Interestingly, it doesn't output anything normally (to the `cmd.exe` window), but it does output when the output is piped or redirected: `C:\usr\local\share\PassThru\perl>"C:\Program Files\Mozilla Firefox\fir +efox.exe" --version C:\usr\local\share\PassThru\perl>"C:\Program Files\Mozilla Firefox\fir +efox.exe" --version \| perl -e "print $_ for <>" Mozilla Firefox 61.0.2 C:\usr\local\share\PassThru\perl>"C:\Program Files\Mozilla Firefox\fir +efox.exe" --version > out.txt C:\usr\local\share\PassThru\perl>type out.txt Mozilla Firefox 61.0.2` [download] I actually first noticed it inside perl, using the piped open described elsewhere, while writing Re^5: Execute command with spaces in perl: `C:\usr\local\share\PassThru\perl>perl -Mwarnings -Mstrict -e "my $cmd += q\|C:\Program Files\Mozilla Firefox\firefox.exe\|; open my $fh, '-\|', + $cmd, '--version' or die $!; my $out = do { local $/; <$fh> }; close + $fh or die $! ? $! : qq(\$?=$?); print $out" Mozilla Firefox 61.0.2` [download]	[reply] [d/l] [select]
Re: Execute command with spaces in perl by haukex (Archbishop) on Aug 27, 2018 at 10:48 UTC
I would strongly recommend you use a module to do this for you, instead of trying to do it yourself. For example, there's `capturex` from IPC::System::Simple, or IPC::Run3, which uses Win32::ShellQuote under the hood on Windows: `use warnings; use strict; use IPC::Run3 'run3'; my $cmd = 'C:\Program Files\Mozilla Firefox\firefox.exe'; run3 [$cmd,'--version'], undef, \my $out or die "run3: $!"; die "\$?=$?" if $?; chomp $out;` [download] If you want to stick with piped open, you could also use Win32::ShellQuote directly to do the quoting for you. I wrote about the above options, as well as the pitfalls with running external commands, at length here, with example code. In this case, since you're running a fixed external command with one or more arguments, you can also use the `LIST` form of open: `use warnings; use strict; my $cmd = 'C:\Program Files\Mozilla Firefox\firefox.exe'; open my $fh, '-\|', $cmd, '--version' or die $!; my $out = do { local $/; <$fh> }; # slurp close $fh or die $! ? $! : "\$?=$?"; chomp $out;` [download] Note how I am also checking close for errors, this is necessary for a piped open. I'm also slupring the entire output of the command into my variable `$out`; in your code you're only fetching the first line of output, despite that you've named your variable `$aarray`.	[reply] [d/l] [select]
Re^2: Execute command with spaces in perl by Lotus1 (Vicar) on Aug 27, 2018 at 13:33 UTC
I got your example to work using 7-zip as shown below. When Windows sees a string with spaces it assumes you are giving it a list of a program and options so it tries to execute the first item in the list. That first item is 'C:\Program' unless you give it double quotes to show the full path to the executable. (Edit: In Corion's answer to the OP quotes are done correctly and fix this issue.) use warnings; use strict; ## works: no command line options my $cmd1 = 'C:\Program Files\7-Zip\7z.exe'; ## works: Double quotes tells Windows where the first argument, the co +mmand, ends. my $cmd2 = '"C:\Program Files\7-Zip\7z.exe" l Win32-Console-0.10.tar.g +z'; ## doesn't work: gives message about 'C:\Program' is not recognized... my $cmd3 = 'C:\Program Files\7-Zip\7z.exe l Win32-Console-0.10.tar.gz' +; foreach my $cmd ( $cmd1, $cmd2, $cmd3 ) { open my $fh, "$cmd\|" or die $!; my $out = do { local $/; <$fh> }; # slurp close $fh or die $! ? $! : "\$?=$?"; print "<<<$out>>>\n"; } __DATA__ <<< 7-Zip 18.05 (x64) : Copyright (c) 1999-2018 Igor Pavlov : 2018-04-30 Usage: 7z <command> [<switches>...] <archive_name> [<file_names>...] <Commands> a : Add files to archive b : Benchmark d : Delete files from archive e : Extract files from archive (without using directory names) h : Calculate hash values for files i : Show information about supported formats l : List contents of archive rn : Rename files in archive t : Test integrity of archive u : Update files to archive x : eXtract files with full paths <Switches> -- : Stop switches parsing @listfile : set path to listfile that contains file names -ai[r[-\|0]]{@listfile\|!wildcard} : Include archives -ax[r[-\|0]]{@listfile\|!wildcard} : eXclude archives -ao{a\|s\|t\|u} : set Overwrite mode -an : disable archive_name field -bb[0-3] : set output log level -bd : disable progress indicator -bs{o\|e\|p}{0\|1\|2} : set output stream for output/error/progress line -bt : show execution time statistics -i[r[-\|0]]{@listfile\|!wildcard} : Include filenames -m{Parameters} : set compression Method -mmt[N] : set number of CPU threads -mx[N] : set compression level: -mx1 (fastest) ... -mx9 (ultra) -o{Directory} : set Output directory -p{Password} : set Password -r[-\|0] : Recurse subdirectories -sa{a\|e\|s} : set Archive name mode -scc{UTF-8\|WIN\|DOS} : set charset for for console input/output -scs{UTF-8\|UTF-16LE\|UTF-16BE\|WIN\|DOS\|{id}} : set charset for list fi +les -scrc[CRC32\|CRC64\|SHA1\|SHA256\|*] : set hash function for x, e, h com +mands -sdel : delete files after compression -seml[.] : send archive by email -sfx[{name}] : Create SFX archive -si[{name}] : read data from stdin -slp : set Large Pages mode -slt : show technical information for l (List) command -snh : store hard links as links -snl : store symbolic links as links -sni : store NT security information -sns[-] : store NTFS alternate streams -so : write data to stdout -spd : disable wildcard matching for file names -spe : eliminate duplication of root folder for extract command -spf : use fully qualified file paths -ssc[-] : set sensitive case mode -sse : stop archive creating, if it can't open some input file -ssw : compress shared files -stl : set archive timestamp from the most recently modified file -stm{HexMask} : set CPU thread affinity mask (hexadecimal number) -stx{Type} : exclude archive type -t{Type} : Set type of archive -u[-][p#][q#][r#][x#][y#][z#][!newArchiveName] : Update options -v{Size}[b\|k\|m\|g] : Create volumes -w[{path}] : assign Work directory. Empty path means a temporary dir +ectory -x[r[-\|0]]{@listfile\|!wildcard} : eXclude filenames -y : assume Yes on all queries >>> <<< 7-Zip 18.05 (x64) : Copyright (c) 1999-2018 Igor Pavlov : 2018-04-30 Scanning the drive for archives: 1 file, 29375 bytes (29 KiB) Listing archive: Win32-Console-0.10.tar.gz -- Path = Win32-Console-0.10.tar.gz Type = gzip Headers Size = 33 Date Time Attr Size Compressed Name ------------------- ----- ------------ ------------ ----------------- +------- 2013-11-28 16:16:37 ..... 153600 29375 Win32-Console-0.1 +0.tar ------------------- ----- ------------ ------------ ----------------- +------- 2013-11-28 16:16:37 153600 29375 1 files >>> With $cmd3 the following goes to STDERR:' 'C:\Program' is not recognized as an internal or external command, operable program or batch file. $?=256 at C:\usr\pm\pipe.pl line 11. [download]	[reply] [d/l]
Re^3: Execute command with spaces in perl by haukex (Archbishop) on Aug 27, 2018 at 13:41 UTC
See Re^2: Having to manually escape quote character in args to "system"? for an interesting discussion on the issue of command-line arguments on Windows. Basically, command line arguments are not passed as a list, but a single big string, and it's up to the called command, not the shell, to interpret that string, and different commands may do that differently.	[reply]
Re^2: Execute command with spaces in perl by naveenp5 (Initiate) on Aug 27, 2018 at 12:06 UTC
Thanks for your suggestion. The '-\|", LIST pipe seems not working on Windows. My script should be able to execute seamlessly between Linux and Windows. Instead when I use the STRING pipe, as mentioned here: https://www.perlmonks.org/bare/?node_id=902198, it again breaks splitting on the space: 'C:\Program' is not recognized as an internal or external command, operable program or batch file. `my $cmd = 'C:\Program Files\Mozilla Firefox\firefox.exe --version'; chomp($cmd); open my $fh2, "$cmd\|" or die $!; my $out = do { local $/; <$fh2> }; # slurp close $fh2 or die $! ? $! : "\$?=$?"; chomp $out;` [download]	[reply] [d/l]
Re^3: Execute command with spaces in perl by haukex (Archbishop) on Aug 27, 2018 at 12:52 UTC
The '-\|", LIST pipe seems not working on Windows. `open my $fh2, "$cmd\|" or die $!;` [download] it again breaks splitting on the space I tested my code before posting, and the `'-\|', LIST` form should work on Windows (Update: at least on Perl 5.22 and up). If it's not working for you, please show the code you're trying and the exact error messages you're getting (How do I post a question effectively? and Short, Self-Contained, Correct Example). The code you posted here is not the `'-\|', LIST` form, which it why it isn't working - why aren't you using the code I showed? With a single string argument, you need to do the quoting correctly; I explained the difference between the two in the node I linked to earlier. If you need `--version` to be variable as well, you could do this: `use warnings; use strict; my @cmd = ('C:\Program Files\Mozilla Firefox\firefox.exe', '--version'); die "\@cmd must have more than one element" unless @cmd>1; open my $fh, '-\|', @cmd or die $!; my $out = do { local $/; <$fh> }; # slurp close $fh or die $! ? $! : "\$?=$?"; chomp $out;` [download] Note I've added the check for `@cmd` having more than one element to make sure the `LIST` form is being used. If for whatever reason you really need the string form, then you'll have to use better quoting, like what is provided by Win32::ShellQuote, or the other modules I named. My script should be able to execute seamlessly between Linux and Windows. The code I showed should work fine on both OSes, except of course for the filename of the Firefox executable; if you've having trouble on Linux, again, please show exactly what that trouble is. For platform-independent filename handling, I recommend the core module File::Spec, or with a nicer interface Path::Class.	[reply] [d/l] [select]
Re^4: Execute command with spaces in perl by Lotus1 (Vicar) on Aug 27, 2018 at 15:01 UTC
Re^5: Execute command with spaces in perl by pryrt (Abbot) on Aug 27, 2018 at 15:50 UTC
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Re^5: Execute command with spaces in perl (updated) by haukex (Archbishop) on Aug 27, 2018 at 15:47 UTC
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