When trying to use backticks for system commands, is there a way to read the error messages if a command doesn't execute properly?
I have no problem getting the results if the command is properly executed.
Ex.
But if I were to do an error command (ex. my @result = `asdf`; ), the error message appears on the console, but @result does not "record" that error message.
Is there a way to record that error message?
Many thanks!
Last edited by radoulov; 10-12-2010 at 04:47 PM..
Reason: Code tags, please!
All,
Does it matter what perl verios your running when you get syntax errors?
on version 5.6.1 the code works fine, but on 5.8.0 the code gets errors?
#!/usr/bin/perl
#use strict;
#use warnings;
my $mess = 'messages';
my $mess1 = 'messages.1';
my $mess2 = 'messages.2';
my... (13 Replies)
Hi - Within perl I want to execute a system command. I want to re-direct all the output from the command to a file (@result = `$cmd`;), but I ALSO want the results to be displayed on the screen (system("$cmd");
The reason is this - if the command completes, I want to process the output. If the... (6 Replies)
Hi,
I am a newbie to PERL and working on a script. When running it I get a lot of compilation errors.
The actual command in the program (which is within a case structure) is given below
# This gives the actual count of inquires from a log file (It works fine when I type this on the... (2 Replies)
Hi,
Can some one please tell me how to redirect only errors to the log file using perl.
Thanks,
Anjan.
---------- Post updated at 08:41 PM ---------- Previous update was at 08:39 PM ----------
Also, i dont want to use any module. Please tell me in normal way (1 Reply)
Hello,
Can't we use backtick operator inside awk.
nawk '
BEGIN {
RS=""; FS="\</input\>"
}
{
for(i=1;i<=NF;i++) {
if ($i~/\"\"/) {
print `grep XYZ $i`;
print $i
}
}
}
' test
In the following code, I need to print $i and some... (8 Replies)
Hi Guys,
Hope everyone is fine :)
I have this code below:
#!/usr/bin/perl
$num_of_files=`ls | grep -v remover | wc -l`;
$remover=`ls -lrt | grep -v total | grep -v remover | head -1 | awk '{print $8}' | rm \`xargs\``;
if ($num_of_files>3) {
system ($remover);
}
When I... (3 Replies)
Hello all,
I have a problem with a bash script. It contains an MySQL query, which when I run it 'as is', executes without a problem.
When, however, I try to get it to assign its output to a variable, using the backtick, I get errors.
So ..
/usr/bin/mysql -N -B mydatabase -e 'SELECT... (3 Replies)
co
#! /usr/bin/perl
use strict;
use warnings;
use diagnostics;
my $amount=""; my $bain; ; my $code="";
my $date;my $day;my $line; my $mo; my $LNUM = 0;
my $xyz=""; my $yr;
$yr = 2015;
my $F; my @F;
while (<>) {
chop;
++$LNUM;
@F = split(';');
if ( $F eq "Date" )... (1 Reply)
When I run this
#!/bin/bash
Block count: 421958912
Reserved block count: 4219589
perl -e "printf(\"%.1lf%%\n\", ($Reserved block count * 100.0 ) / $Block count);"
I get these error messages. Can someone please help me?
andyk_~/Downloads$ Show_Percent_Reserved_Blocks.sh... (4 Replies)
Discussion started by: drew77
4 Replies
LEARN ABOUT BSD
exec
exec(1) User Commands exec(1)NAME
exec, eval, source - shell built-in functions to execute other commands
SYNOPSIS
sh
exec [argument...]
eval [argument...]
csh
exec command
eval argument...
source [-h] name
ksh
*exec [arg...]
*eval [arg...]
DESCRIPTION
sh
The exec command specified by the arguments is executed in place of this shell without creating a new process. Input/output arguments may
appear and, if no other arguments are given, cause the shell input/output to be modified.
The arguments to the eval built-in are read as input to the shell and the resulting command(s) executed.
csh
exec executes command in place of the current shell, which terminates.
eval reads its arguments as input to the shell and executes the resulting command(s). This is usually used to execute commands generated as
the result of command or variable substitution.
source reads commands from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descrip-
tors. An error in a sourced file at any level terminates all nested source commands.
-h Place commands from the file name on the history list without executing them.
ksh
With the exec built-in, if arg is given, the command specified by the arguments is executed in place of this shell without creating a new
process. Input/output arguments may appear and affect the current process. If no arguments are given the effect of this command is to mod-
ify file descriptors as prescribed by the input/output redirection list. In this case, any file descriptor numbers greater than 2 that are
opened with this mechanism are closed when invoking another program.
The arguments to eval are read as input to the shell and the resulting command(s) executed.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
EXIT STATUS
For ksh:
If command is not found, the exit status is 127. If command is found, but is not an executable utility, the exit status is 126. If a redi-
rection error occurs, the shell exits with a value in the range 1-125. Otherwise, exec returns a zero exit status.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), ksh(1), sh(1), attributes(5)SunOS 5.10 17 Jul 2002 exec(1)