I would like to execute any bash command. I found Command::new but I'm unable to execute "complex" commands such as ls ; sleep 1; ls. Moreover, even if I put this in a bash script, and execute it, I will only have the result at the end of the script (as it is explain in the process doc). I would like to get the result as soon as the command prints it (and to be able to read input as well) the same way we can do it in bash.
Command::new is indeed the way to go, but it is meant to execute a program. ls ; sleep 1; ls is not a program, it's instructions for some shell. If you want to execute something like that, you would need to ask a shell to interpret that for you:
Command::new("/usr/bin/sh").args(&["-c", "ls ; sleep 1; ls"])
// your complex command is just an argument for the shell
To get the output, there are two ways:
the output method is blocking and returns the outputs and the exit status of the command.
the spawn method is non-blocking, and returns a handle containing the child's process stdin, stdout and stderr so you can communicate with the child, and a wait method to wait for it to cleanly exit. Note that by default the child inherits its parent file descriptor and you might want to set up pipes instead:
You should use something like:
let child = Command::new("/usr/bin/sh")
.args(&["-c", "ls sleep 1 ls"])
.stderr(std::process::Stdio::null()) // don't care about stderr
.stdout(std::process::Stdio::piped()) // set up stdout so we can read it
.stdin(std::process::Stdio::piped()) // set up stdin so we can write on it
.spawn().expect("Could not run the command"); // finally run the command
write_something_on(child.stdin);
read(child.stdout);
I am using the blobstor command to load jpeg images into an ingres db, which is fine. But at some point I need to develop a manual way to copy them back out again.
I can find some examples of this that uses BCP, however these are for sql server db's. So my question is, does blobstor have an equal an opposite command to extract blobs, that can be used when select from an Ingres db. Pointers to any examples would be much appreciated.
I don't believe there is a blobstor-opposite tool which ships with Ingres, when I've had need for such a thing before now the solution was to write a short program.
As an example, here's a perl script. It uses DBI and the DBD-IngresII module. Hope it's of some use.
# Required: db=, table=, col=. Optional: user=.
# Anything else is a where clause.
use DBI;
my %p=(); my $where="";
foreach my $arg (#ARGV)
{
if ($arg =~ /(db|table|col|user)=(\S+)$/) { $p{$1}=$2; next; }
$where .= " ".$arg if($p{db} and $p{table} and $p{col});
}
die "db, table and col required.\n" if(!$p{db} or !$p{table}
or !$p{col});
my $user=""; $user=$p{user} if defined($p{user});
my $dbh=DBI->connect("dbi:IngresII:".$p{db},$user,"");
my $stm="select ".$p{col}." from ".$p{table};
$stm.=" where".$where if ($where ne "");
my $sth=$dbh->prepare($stm);
$sth->execute;
#row=$sth->fetchrow_array;
print $row[0];
$sth->finish;
$dbh->disconnect;
I am unfamiliar with linux/linux environment so do pardon me if I make any mistakes, do comment to clarify.
I have created a simple perl script. This script creates a sql file and as shown, it would execute the lines in the file to be inserted into the database.
#!/usr/bin/perl
use strict;
use warnings;
use POSIX 'strftime';
my $SQL_COMMAND;
my $HOST = "i";
my $USERNAME = "need";
my $PASSWORD = "help";
my $NOW_TIMESTAMP = strftime '%Y-%m-%d_%H-%M-%S', localtime;
open my $out_fh, '>>', "$NOW_TIMESTAMP.sql" or die 'Unable to create sql file';
printf {$out_fh} "INSERT INTO BOL_LOCK.test(name) VALUES ('wow');";
sub insert()
{
my $SQL_COMMAND = "mysql -u $USERNAME -p'$PASSWORD' ";
while( my $sql_file = glob '*.sql' )
{
my $status = system ( "$SQL_COMMAND < $sql_file" );
if ( $status == 0 )
{
print "pass";
}
else
{
print "fail";
}
}
}
insert();
This works if I execute it while I am logged in as a user(I do not have access to Admin). However, when I set a cronjob to run this file let's say at 10.08am by using the line(in crontab -e):
08 10 * * * perl /opt/lampp/htdocs/otpms/Data_Tsunami/scripts/test.pl > /dev/null 2>&1
I know the script is being executed as the sql file is created. However no new rows are inserted into the database after 10.08am. I've searched for solutions and some have suggested using the DBI module but it's not available on the server.
EDIT: Didn't manage to solve it in the end. A root/admin account was used to to execute the script so that "solved" the problem.
First things first, get rid of the > /dev/null 2>&1 at the end of your crontab entry (at least temporarily) so you can actually see any errors that may be occurring.
In other words, change it temporarily to something like:
08 10 * * * perl /opt/lampp/htdocs/otpms/Data_Tsunami/scripts/test.pl >/tmp/myfile 2>&1
Then you can examine the /tmp/myfile file to see what's being output.
The most likely case is that mysql is not actually on the path in your cron job, because cron itself gives a rather minimal environment.
To fix that problem (assuming that's what it is), see this answer, which gives some guidelines on how best to expand the cron environment to give you what you need. That will probably just involve adding the MySQL executable directory to your PATH variable.
The other thing you may want to consider is closing the out_fh file before trying to pass it to mysql - if the buffers haven't been flushed, it may still be an empty file as far as other processes are concerned.
The expression glob(".* *") matches all files in the current working
directory.
- http://perldoc.perl.org/functions/glob.html
you should not rely on the wd in a cron job. If you want to use a glob (or any file operation) with a relative path, set the wd with chdir first.
source: http://www.perlmonks.org/bare/?node_id=395387
So if your working directory is, for example /home/user, you should insert
chdir('/home/user/');
before the WHILE, ie:
sub insert()
{
my $SQL_COMMAND = "mysql -u $USERNAME -p'$PASSWORD' ";
chdir('/home/user/');
while( my $sql_file = glob '*.sql' )
{
...
replace /home/user with wherever your sql files are being created.
It's better to do as much processing within Perl as possible. It avoids the overhead of generating a separate shell process and leaves everything under the control of the program so that you can handle any errors much more simply
Database access from Perl is done using the DBI module. This program demonstrates how to achieve what you have written using the mysql utility. As you can see it's also much more concise
#!/usr/bin/perl
use strict;
use warnings;
use DBI;
my $host = "i";
my $username = "need";
my $password = "help";
my $dbh = DBI->connect("DBI:mysql:database=test;host=$host", $username, $password);
my $insert = $dbh->prepare('INSERT INTO BOL_LOCK.test(name) VALUES (?)');
my $rv = $insert->execute('wow');
print $rv ? "pass\n" : "fail\n";
Im having an issue writing a DCL in OpenVMS in that I need the DCL to call a command and capture its output (but not output the output to the screen) Later on in the DCL I then need to print that output I stored.
Heres an example:
ICE SET FASTER !This command sets my environment to the "Faster" environment.
The above command outputs this if executed directly in OpenVMS:
Initialising TEST Environment to FASTER
--------------------------------------------------------------------------------
Using Test Search rules FASTER
Using Test Search rules FASTER
--------------------------------------------------------------------------------
dcl>
So I created a DCL in an attempt to wrap this output in order to display a more simplified output. Heres my code so far:
!************************************************************************
$ !* Wrapper for setting ICE account. Outputs Environment
$ !************************************************************************
$ on error then goto ABORT_PROCESS
$ICE_DCL_MAIN:
$ ice set 'P1'
$ ICE SHOW
$ EXIT
$ABORT_PROCESS:
$ say "Error ICING to: " + P1
$ EXIT 2
[End of file]
In the lines above ICE SET 'P1' is setting the ice environment, but I dont want this output to be echoed to VMS. But what I do want is to write the output of $ICE SHOW into a variable and then echo that out later on in the DCL (most of which ive omitted for simplification purposes)
So what should be outputted should be:
current Test Environment is DISK$DEVELOPERS:[FASTER.DEVELOP]
Instead of:
Initialising TEST Environment to FASTER
--------------------------------------------------------------------------------
Using Test Search rules FASTER
Using Test Search rules FASTER
--------------------------------------------------------------------------------
current Test Environment is DISK$DEVELOPERS:[FASTER.DEVELOP]
Ive had a look through the manual and im getting a bit confused so I figured I tried here. Id appreciate any pointers. Thanks.
EDIT
Here is what ive come up with after the comments, the problem im having is when I connect to VMS using an emulator such as SecureCRT the correct output is echoed. But when I run the DCL via my SSH2 library in .NET it doesnt output anything. I guess thats because it closes the SYS$OUTPUT stream temporarily or something?
$ !************************************************************************
$ !* Wrapper for setting ICE account. Outputs Environment
$ !************************************************************************
$ on error then goto ABORT_PROCESS
$ICE_DCL_MAIN:
$ DEFINE SYS$OUTPUT NL:
$ ice set 'P1'
$ DEASSIGN SYS$OUTPUT
$ ice show
$ EXIT
$ABORT_PROCESS:
$ say "Error ICING to: " + P1
$ EXIT 2
[End of file]
EDIT 2
So I guess really I need to clarify what im trying to do here. Blocking the output doesnt so matter so much, im merely trying to capture it into a Symbol for example.
So in C# for example you can have a method that returns a string. So you'd have string myResult = vms.ICETo("FASTER"); and it would return that and store it in the variable.
I guess im looking for a similar thing in VMS so that once ive iced to the environment I can call:
$ environment == $ICE SHOW
But I of course get errors with that statement
The command $ assign/user_mode Thing Sys$Output will cause output to be redirected to Thing until you $ deassign/user_mode Sys$Output or next executable image exits. An assignment without the /USER_MODE qualifier will persist until deassigned.
Thing can be a logical name, a file specification (LOG.TXT) or the null device (NLA0:) if you simply want to flush the output.
When a command procedure is executed the output can be redirected using an /OUTPUT qualifier, e.g. $ #FOO/output=LOG.TXT.
And then there is piping ... .
You can redirect the output to a temp file and then print its content later:
$ pipe write sys$output "hi" > tmp.tmp
$ ty tmp.tmp
VMS is not Unix, DCL is not Bash: you can not easily set a DCL symbol from the output of a command.
Your ICE SHOW prints one line, correct? The first word is always "current", correct?
So you can create a hack.
First let me fake your ICE command:
$ create ice.com
$ write sys$output "current Test Environment is DISK$DEVELOPERS:[FASTER.DEVELOP]"
^Z
$
and I define a dcl$path pointing to the directory where this command procedure is
so that I can use/fake the command ICE
$ define dcl$path sys$disk[]
$ ice show
current Test Environment is DISK$DEVELOPERS:[FASTER.DEVELOP]
$
Now what you need, create a command procedure which sets a job logical
$ cre deflog.com
$ def/job/nolog mylog "current''p1'"
^Z
$
And I define a command "current" to run that command procedure:
$ current="#deflog """
Yes, you need three of the double quotes at the end of the line!
And finally:
$ pipe (ice show | #sys$pipe) && mysym="''f$log("mylog")'"
$ sh symb mysym
MYSYM = "current Test Environment is DISK$DEVELOPERS:[FASTER.DEVELOP]"
$
On the other hand, I don't know what you are referring to C# and Java. Can you elaborate on that and tell us what runs where?
You can try using: DEFINE /USER SYS$OUTPUT NL:.
It works only for the next command and you dont need to deassign.
Sharing some of my experience here. I used below methods to redirect outputs to files.
Define/Assign the user output and then execute the required command/script afterwards. Output will be written to .
$define /user sys$output <file_path>
execute your command/script
OR
assign /user <file_path> sys$output
execute your command/script
deassign sys$output
To re-direct in to null device like in Unix (mentioned in above answers), you can use 'nl:' instead of
define /user sys$output nl:
or
assign /user nl: sys$output
It's the first great virtue of programmers. All of us have, at one time or another automated a task with a bit of throw-away code. Sometimes it takes a couple seconds tapping out a one-liner, sometimes we spend an exorbitant amount of time automating away a two-second task and then never use it again.
What tiny hack have you found useful enough to reuse? To make go so far as to make an alias for?
Note: before answering, please check to make sure it's not already on favourite command-line tricks using BASH or perl/ruby one-liner questions.
i found this on dotfiles.org just today. it's very simple, but clever. i felt stupid for not having thought of it myself.
###
### Handy Extract Program
###
extract () {
if [ -f $1 ] ; then
case $1 in
*.tar.bz2) tar xvjf $1 ;;
*.tar.gz) tar xvzf $1 ;;
*.bz2) bunzip2 $1 ;;
*.rar) unrar x $1 ;;
*.gz) gunzip $1 ;;
*.tar) tar xvf $1 ;;
*.tbz2) tar xvjf $1 ;;
*.tgz) tar xvzf $1 ;;
*.zip) unzip $1 ;;
*.Z) uncompress $1 ;;
*.7z) 7z x $1 ;;
*) echo "'$1' cannot be extracted via >extract<" ;;
esac
else
echo "'$1' is not a valid file"
fi
}
Here's a filter that puts commas in the middle of any large numbers in standard input.
$ cat ~/bin/comma
#!/usr/bin/perl -p
s/(\d{4,})/commify($1)/ge;
sub commify {
local $_ = shift;
1 while s/^([ -+]?\d+)(\d{3})/$1,$2/;
return $_;
}
I usually wind up using it for long output lists of big numbers, and I tire of counting decimal places. Now instead of seeing
-rw-r--r-- 1 alester alester 2244487404 Oct 6 15:38 listdetail.sql
I can run that as ls -l | comma and see
-rw-r--r-- 1 alester alester 2,244,487,404 Oct 6 15:38 listdetail.sql
This script saved my career!
Quite a few years ago, i was working remotely on a client database. I updated a shipment to change its status. But I forgot the where clause.
I'll never forget the feeling in the pit of my stomach when I saw (6834 rows affected). I basically spent the entire night going through event logs and figuring out the proper status on all those shipments. Crap!
So I wrote a script (originally in awk) that would start a transaction for any updates, and check the rows affected before committing. This prevented any surprises.
So now I never do updates from command line without going through a script like this. Here it is (now in Python):
import sys
import subprocess as sp
pgm = "isql"
if len(sys.argv) == 1:
print "Usage: \nsql sql-string [rows-affected]"
sys.exit()
sql_str = sys.argv[1].upper()
max_rows_affected = 3
if len(sys.argv) > 2:
max_rows_affected = int(sys.argv[2])
if sql_str.startswith("UPDATE"):
sql_str = "BEGIN TRANSACTION\\n" + sql_str
p1 = sp.Popen([pgm, sql_str],stdout=sp.PIPE,
shell=True)
(stdout, stderr) = p1.communicate()
print stdout
# example -> (33 rows affected)
affected = stdout.splitlines()[-1]
affected = affected.split()[0].lstrip('(')
num_affected = int(affected)
if num_affected > max_rows_affected:
print "WARNING! ", num_affected,"rows were affected, rolling back..."
sql_str = "ROLLBACK TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
sql_str = "COMMIT TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
ret_code = sp.call([pgm, sql_str], shell=True)
I use this script under assorted linuxes to check whether a directory copy between machines (or to CD/DVD) worked or whether copying (e.g. ext3 utf8 filenames -> fusebl
k) has mangled special characters in the filenames.
#!/bin/bash
## dsum Do checksums recursively over a directory.
## Typical usage: dsum <directory> > outfile
export LC_ALL=C # Optional - use sort order across different locales
if [ $# != 1 ]; then echo "Usage: ${0/*\//} <directory>" 1>&2; exit; fi
cd $1 1>&2 || exit
#findargs=-follow # Uncomment to follow symbolic links
find . $findargs -type f | sort | xargs -d'\n' cksum
Sorry, don't have the exact code handy, but I coded a regular expression for searching source code in VS.Net that allowed me to search anything not in comments. It came in very useful in a particular project I was working on, where people insisted that commenting out code was good practice, in case you wanted to go back and see what the code used to do.
I have two ruby scripts that I modify regularly to download all of various webcomics. Extremely handy! Note: They require wget, so probably linux. Note2: read these before you try them, they need a little bit of modification for each site.
Date based downloader:
#!/usr/bin/ruby -w
Day = 60 * 60 * 24
Fromat = "hjlsdahjsd/comics/st%Y%m%d.gif"
t = Time.local(2005, 2, 5)
MWF = [1,3,5]
until t == Time.local(2007, 7, 9)
if MWF.include? t.wday
`wget #{t.strftime(Fromat)}`
sleep 3
end
t += Day
end
Or you can use the number based one:
#!/usr/bin/ruby -w
Fromat = "http://fdsafdsa/comics/%08d.gif"
1.upto(986) do |i|
`wget #{sprintf(Fromat, i)}`
sleep 1
end
Instead of having to repeatedly open files in SQL Query Analyser and run them, I found the syntax needed to make a batch file, and could then run 100 at once. Oh the sweet sweet joy! I've used this ever since.
isqlw -S servername -d dbname -E -i F:\blah\whatever.sql -o F:\results.txt
This goes back to my COBOL days but I had two generic COBOL programs, one batch and one online (mainframe folks will know what these are). They were shells of a program that could take any set of parameters and/or files and be run, batch or executed in an IMS test region. I had them set up so that depending on the parameters I could access files, databases(DB2 or IMS DB) and or just manipulate working storage or whatever.
It was great because I could test that date function without guessing or test why there was truncation or why there was a database ABEND. The programs grew in size as time went on to include all sorts of tests and become a staple of the development group. Everyone knew where the code resided and included them in their unit testing as well. Those programs got so large (most of the code were commented out tests) and it was all contributed by people through the years. They saved so much time and settled so many disagreements!
I coded a Perl script to map dependencies, without going into an endless loop, For a legacy C program I inherited .... that also had a diamond dependency problem.
I wrote small program that e-mailed me when I received e-mails from friends, on an rarely used e-mail account.
I wrote another small program that sent me text messages if my home IP changes.
To name a few.
Years ago I built a suite of applications on a custom web application platform in PERL.
One cool feature was to convert SQL query strings into human readable sentences that described what the results were.
The code was relatively short but the end effect was nice.
I've got a little app that you run and it dumps a GUID into the clipboard. You can run it /noui or not. With UI, its a single button that drops a new GUID every time you click it. Without it drops a new one and then exits.
I mostly use it from within VS. I have it as an external app and mapped to a shortcut. I'm writing an app that relies heavily on xaml and guids, so I always find I need to paste a new guid into xaml...
Any time I write a clever list comprehension or use of map/reduce in python. There was one like this:
if reduce(lambda x, c: locks[x] and c, locknames, True):
print "Sub-threads terminated!"
The reason I remember that is that I came up with it myself, then saw the exact same code on somebody else's website. Now-adays it'd probably be done like:
if all(map(lambda z: locks[z], locknames)):
print "ya trik"
I've got 20 or 30 of these things lying around because once I coded up the framework for my standard console app in windows I can pretty much drop in any logic I want, so I got a lot of these little things that solve specific problems.
I guess the ones I'm using a lot right now is a console app that takes stdin and colorizes the output based on xml profiles that match regular expressions to colors. I use it for watching my log files from builds. The other one is a command line launcher so I don't pollute my PATH env var and it would exceed the limit on some systems anyway, namely win2k.
I'm constantly connecting to various linux servers from my own desktop throughout my workday, so I created a few aliases that will launch an xterm on those machines and set the title, background color, and other tweaks:
alias x="xterm" # local
alias xd="ssh -Xf me#development_host xterm -bg aliceblue -ls -sb -bc -geometry 100x30 -title Development"
alias xp="ssh -Xf me#production_host xterm -bg thistle1 ..."
I have a bunch of servers I frequently connect to, as well, but they're all on my local network. This Ruby script prints out the command to create aliases for any machine with ssh open:
#!/usr/bin/env ruby
require 'rubygems'
require 'dnssd'
handle = DNSSD.browse('_ssh._tcp') do |reply|
print "alias #{reply.name}='ssh #{reply.name}.#{reply.domain}';"
end
sleep 1
handle.stop
Use it like this in your .bash_profile:
eval `ruby ~/.alias_shares`