system call - how-to.
in [Perl]
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From: elsiddik on 1 May 2007 07:22 well i wanted to just mess a little with perl and try if it can give me the same result of a small shell script i wrote a little while ago but it doesnt seems to work out with me . here is my shell script #!/bin/bash DIRECTORY="/usr/bin" for file in $DIRECTORY/* do whatis `basename $file` done exit 0 i tried to run a similiar perl code by typing on command line. perl -e "system qw (whatis /usr/bin/*)" but its not giving me the same whatislog - what am i doing wrong ? cheers. zaher el siddik
From: Paul Lalli on 1 May 2007 08:45 On May 1, 7:22 am, elsiddik <elsid...(a)gmail.com> wrote: > well i wanted to just mess a little with perl and try if it can give > me the same result of a small shell script i wrote a little while ago > but it doesnt seems to work out with me . here is my shell script > > #!/bin/bash > DIRECTORY="/usr/bin" > for file in $DIRECTORY/* > do whatis `basename $file` > > done > exit 0 > > i tried to run a similiar perl code by typing on command line. > > perl -e "system qw (whatis /usr/bin/*)" > > but its not giving me the same whatislog - what am i doing wrong ? You are using the qw operator. This operator takes a space-separated list of barewords and returns a quoted list of words. That is, your system() call is equivalent to: system('whatis', '/usr/bin/*'); When you call system() with two or more arguments, Perl executes the first argument directly, passing in the remaining arguments. It does not spawn a shell at all. So the * in the second argument there is not interpreted by any shell to mean "all files", because there is no shell to do the interpreting. So you are litterally calling "whatis" on the single argument "/usr/bin/*". Since no such file with that name exists, there is no output. Change your qw() to qq() or q(), and read up on `perldoc -f system` for more information. Paul Lalli
From: Klaus on 1 May 2007 11:13 > > On May 1, 7:22 am, elsiddik <elsid...(a)gmail.com> wrote: > > > perl -e "system qw (whatis /usr/bin/*)" > > > but its not giving me the same whatislog - what am i doing wrong ? > On May 1, 10:45 pm, Paul Lalli <mri...(a)gmail.com> wrote: > > You are using the qw operator. > > Change your qw() to qq() or q() On May 1, 3:11 pm, elsiddik <elsid...(a)gmail.com> wrote: > well i tried running the code with q and qq > my $path = "/usr/bin/"; > system "whatis $path"; > its confusing me big time. It's confusing you, probably because you forgot to put an asterisk at the end of /usr/bin/ -- Klaus
From: Paul Lalli on 1 May 2007 13:12 > > On May 1, 7:22 am, elsiddik <elsid...(a)gmail.com> wrote: > > > > perl -e "system qw (whatis /usr/bin/*)" > > > > but its not giving me the same whatislog - what am i doing wrong ? > > > You are using the qw operator. This operator takes a space-separated > > list of barewords and returns a quoted list of words. That is, your > > system() call is equivalent to: > > system('whatis', '/usr/bin/*'); > > > Change your qw() to qq() or q(), and read up on `perldoc -f system` > > for more information. > well i tried running the code with q and qq but im still getting the > same output -- I don't believe you. Please post a short-but-complete script that demonstrates this, like so: $ perl -e'system qq(whatis /usr/bin/*)' acctcom acctcom (1) - search and print process accounting files activation-client activation-client () - bonobo- activationdebugging tool adb adb (1) - general-purpose debugger <remainder snipped> > the part that i cant understand is when you run the shell script - i > could see all the /usr/bin/files output with <whatis> details , > with perls everything looks quiet good also but instead of the > <whatis> details - keeps giving me /usr/bin/filename: nothing > appropriate. Again, post a short-but-complete script that generates this output. > i even tried to write a perl script - used File::Basename I have no idea what you think File::Basename has to do with this. > <code> > > #!/usr/bin/perl -w > > use strict; > use warnings; > > use File::Basename; > > my $path = "/usr/bin/"; > my $files = basename($path); > my $dir = dirname($path); I still have no idea what you think File::Basename has to do with this. > print "dir is $dir , files is $files\n"; Didn't that output tell you you're doing something very wrong? It should have claimed that $dir is /usr and $files is the empty string. > system "whatis $path"; Now you're just calling whatis on "/usr/bin/", rather than on all the files in /usr/bin. Why did you omit the * this time? Paul Lalli
From: Jim Gibson on 1 May 2007 19:44
In article <1178039561.065663.196510(a)l77g2000hsb.googlegroups.com>, Paul Lalli <mritty(a)gmail.com> wrote: > > > On May 1, 7:22 am, elsiddik <elsid...(a)gmail.com> wrote: > > > > > > perl -e "system qw (whatis /usr/bin/*)" > > > > > > but its not giving me the same whatislog - what am i doing wrong ? > > > > > You are using the qw operator. This operator takes a space-separated > > > list of barewords and returns a quoted list of words. That is, your > > > system() call is equivalent to: > > > system('whatis', '/usr/bin/*'); > > > > > Change your qw() to qq() or q(), and read up on `perldoc -f system` > > > for more information. > > > well i tried running the code with q and qq but im still getting the > > same output -- > > I don't believe you. Please post a short-but-complete script that > demonstrates this, like so: > > $ perl -e'system qq(whatis /usr/bin/*)' > acctcom acctcom (1) - search and print process accounting > files > activation-client activation-client () - bonobo- > activationdebugging tool > adb adb (1) - general-purpose debugger > <remainder snipped> On my system (Mac OS 10.4.9), "whatis /usr/bin/anything" gives: /usr/bin/anything: nothing appropriate I have to do whatis anything so "perl -e'system qq(whatis /usr/bin/*)' give a long list of "nothing appropriate". I can fix this with the Unix basename utility: perl -e 'system(qq(whatis `basename /usr/bin/*`));' > > > the part that i cant understand is when you run the shell script - i > > could see all the /usr/bin/files output with <whatis> details , > > with perls everything looks quiet good also but instead of the > > <whatis> details - keeps giving me /usr/bin/filename: nothing > > appropriate. > > Again, post a short-but-complete script that generates this output. > > > i even tried to write a perl script - used File::Basename > > I have no idea what you think File::Basename has to do with this. As above. -- Jim Gibson Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY ** ---------------------------------------------------------- http://www.usenet.com |