#!/usr/bin/expect
set NUM [exec some command to ssh to a remote machine and return a number]
puts $NUM
while { $NUM != "0" } {
set NUM [exec some command to ssh to a remote machine and return a number]
sleep 5
}
The above is my code. It runs in an expect script. I want to assign the variable NUM to some command that ssh to a remote machine and return a number (this command will return a number when I type in the terminal).
And I got the error:
100
while executing
"exec some command to ssh to a remote machine and return a number "qstat | wc -l""
invoked from within
"set JOBS [exec some command to ssh to a remote machine and return a number "qstat | wc -l"]"
The thing is that I have got the number but I failed to assign that number to the variable NUM
Can anyone help me to debug this piece? Thanks
Yon cannot do it because its an expect script, the best way to do it is to wrap the expect script in a bash script. see Run expect command inside while loop in shell script
Related
I have a long list of remote hosts and I want to run a shell command on all of them. The command takes a very long time, so I want to run the command inside screen on the remote machine, disconnecting immediately from each, and I want the terminal output on the remote to be preserved after the command exits. There is a "tag" that should be supplied to each command as an argument. I tried to do this with parallel, something like this:
$ cat servers.txt
user1#server1.example.com/tag1
user2#server2.example.com/tag2
# ...
$ cat run.sh
grep -v '^#' servers.txt |
parallel ssh -tt '{//}' \
'tag={/}; exec screen slow_command --option1 --option2 $tag other args'
This doesn't work: all of the remote processes are launched, but they are not detached (so the ssh sessions remain live and I don't get my local shell back), and once each command finishes, its screen exits immediately and the output is lost.
How do I fix this script? Note: if this is easier to do with tmux and/or some other marshalling program besides parallel, I'm happy to hear answers that explain how to do it that way.
Something like this:
grep -v '^#' servers.txt |
parallel -q --colsep / ssh {1} "screen -d -m bash -c 'echo do stuff \"{2}\";sleep 1000000'"
The final sleep makes sure the screen does not die. You will have 1000000 seconds to attach to it and kill it.
There is an awful lot of quoting there - especially if do stuff is complex.
It may be easier to make a function that computes tag on the remote machine. You need GNU Parallel 20200522 for this:
env_parallel --session
f() {
sshlogin="$1"
# TODO given $sshlogin compute $tag (e.g. a table lookup)
do_stuff() {
echo "do stuff $tag"
sleep 1000000
}
export -f do_stuff
screen -d -m bash -c do_stuff "$#"
}
env_parallel --nonall --slf servers_without_tag f '$PARALLEL_SSHLOGIN'
env_parallel --endsession
Need to check for distribution of a file in an array programmatically. Logging into a master server and then would like to check for file on workers using simple ssh. So far I have:
ssh $HOSTNAME "[ -e '$HOSTNAME:/directory/filename' ] && echo 'Exists'"
Based on some of the logging output, I know the ssh is successful, but how can I get the test to return a message to the master server? Running the above returns nothing.
SSH will exit with the same exit code as the command that you run on the remote host. If that command is a test, then the exit code will match what you would normally expect from a test.
I would suggest the following:
Simplify your command to only run the test over SSH
Run the echo on your local machine
It doesn't seem correct that you have $HOSTNAME: in front of your path.
ssh "$HOSTNAME" "test -e '/directory/filename'" && echo 'Exists'
I personally find if statements to be much more easily understandable, which is an optional change if you are willing to go that route:
if ssh "$HOSTNAME" "test -e '/directory/filename'"; then
echo "Exists"
else
echo "Does not exist" >&2
exit 1
fi
Below is a simple example of what I'm trying to accomplish. I'm trying to force an ssh script to not wait for all child processes to exit before returning. The purpose is to launch a daemon process on a remote host via ssh.
test.sh
#!/bin/bash
(
sleep 2
echo "done"
) &
When I run the script on the console it returns immediately, with "done" appearing 2 seconds later.
When I run the script as an ssh script, the ssh command . It appears to wait until all child processes have terminated until ssh exits.
ssh example
$ ssh mike#127.0.0.1 /home/mike/test.sh
(2 seconds)
done
standard terminal example
$ ./test.sh
$
(2 seconds)
done
How can I make ssh return when the parent/main process has terminated?
EDIT:
I'm aware of the -f option to ssh to run the process in the background . It leaves the ssh process and connection open on the source host. For my purposes this is unsuitable.
ssh mike#127.0.0.1 /home/mike/test.sh
When you run ssh in this fashion, the remote ssh server will create a set of pipes (or socketpairs) which become the standard input, output, and error for the process which you requested it to run, in this case the script process. The ssh server doesn't end the session based on when the script process exits. Instead, it ends the session when it reads and end-of-file indication on the script process's standard output and standard error.
In your case, the script process creates a child process which inherits the script's standard input, output, and error. A pipe (or socketpair) only returns EOF when all possible writers have exited or closed their end of the pipe. As long as the child process is running and has a copy of the standard output/error file descriptors, the ssh server won't read an EOF indication on those descriptors and it won't close the session.
You can get around this by redirecting standard input and standard output in the command that you pass to the remote server:
ssh mike#127.0.0.1 '/home/mike/test.sh > /dev/null 2>&1'
(note the quotes are important)
This avoids passing the standard output and standard error created by the ssh server to the script process or the subprocesses that it creates.
Alternately, you could add a redirection to the script:
#!/bin/bash
(
exec > /dev/null 2>&1
sleep 2
echo "done"
) &
This causes the script's child process to close its copies of the original standard output and standard error.
How can I log Asterisk service (service status, e.g. service is running or stopped) and Asterisk errors in a remote database?
so, with the /etc/asterisk.logger.conf you can have errors go to a syslog, which you can parse for errors and put into a DB. To check the status I recommend a bash script that looks for asterisk running and sends that status to mysql (if last column ordered by datetime) is different then the current status insert it into the db. You can use cron to check status every few minutes.
#!/bin/bash
APP=`ps -aux | grep -v 'grep' | grep 'asterisk'`
# 1 is false in BASH
APP_RUNNING=1
if [ $APP != "" ];
then
APP_RUNNING=0
fi
Here is the scenario,
$hostname
server1
I have the below script in server1,
#!/bin/ksh
echo "Enter server name:"
read server
rsh -n ${server} -l mquser "/opt/hd/ca/scripts/envscripts.ksh"
qdisplay
# script ends.
In above script I am logging into another server say server2 and executing the script "envscripts.ksh" which sets few alias(Alias "qdisplay") defined in it.
I can able to successfully login to server1 but unable to use the alias set by script "envscripts.ksh".
Geting below error,
-bash: qdisplay: command not found
can some please point out what needs to be corrected here.
Thanks,
Vignesh
The other responses and comments are correct. Your rsh command needs to execute both the ksh script and the subsequent command in the same invocation. However, I thought I'd offer an additional suggestion.
It appears that you are writing custom instrumentation for WebSphere MQ. Your approach is to remote shell to the WMQ server and execute a command to display queue attributes (probably depth).
The objective of writing your own instrumentation is admirable, however attempting to do it as remote shell is not an optimal approach. It requires you to maintain a library of scripts on each MQ server and in some cases to maintain these scripts in different languages.
I would suggest that a MUCH better approach is to use the MQSC client available in SupportPac MO72. This allows you to write the scripts once, and then execute them from a central server. Since the MQSC commands are all done via MQ client, the same script handles Windows, UNIX, Linux, iSeries, etc.
For example, you could write a script that remotely queried queue depths and printed a list of all queues with depth > 0. You could then either execute this script directly against a given queue manager or write a script to iterate through a list of queue managers and collect the same report for the entire network. Since the scripts are all running on the one central server, you do not have to worry about getting $PATH right, differences in commands like tr or grep, where ksh or perl are installed, etc., etc.
Ten years ago I wrote the scripts you are working on when my WMQ network was small. When the network got bigger, these platform differences ate me alive and I was unable to keep the automation up and running. When I switched to using WMQ client and had only one set of scripts I was able to keep it maintained with far less time and effort.
The following script assumes that the QMgr name is the same as the host name except in UPPER CASE. You could instead pass QMgr name, hostname, port and channel on the command line to make the script useful where QMgr names do not match the host name.
#!/usr/bin/perl -w
#-------------------------------------------------------------------------------
# mqsc.pl
#
# Wrapper for M072 SupportPac mqsc executable
# Supply parm file name on command line and host names via STDIN.
# Program attempts to connect to hostname on SYSTEM.AUTO.SVRCONN and port 1414
# redirecting parm file into mqsc.
#
# Intended usage is...
#
# mqsc.pl parmfile.mqsc
# host1
# host2
#
# -- or --
#
# mqsc.pl parmfile.mqsc < nodelist
#
# -- or --
#
# cat nodelist | mqsc.pl parmfile.mqsc
#
#-------------------------------------------------------------------------------
use strict;
$SIG{ALRM} = sub { die "timeout" };
$ENV{PATH} =~ s/:$//;
my $File = shift;
die "No mqsc parm file name supplied!" unless $File;
die "File '$File' does not exist!\n" unless -e $File;
while () {
my #Results;
chomp;
next if /^\s*[#*]/; # Allow comments using # or *
s/^\s+//; # Delete leading whitespace
s/\s+$//; # Delete trailing whitespace
# Do not accept hosts with embedded spaces in the name
die "ERROR: Invalid host name '$_'\n" if /\s/;
# Silently skip blank lines
next unless ($_);
my $QMgrName = uc($_);
#----------------------------------------------------------------------------
# Run the parm file in
eval {
alarm(10);
#Results = `mqsc -E -l -h $_ -p detmsg=1,prompt="",width=512 -c SYSTEM.AUTO.SVRCONN &1 | grep -v "^MQSC Ended"`;
};
if ($#) {
if ($# =~ /timeout/) {
print "Timed out connecting to $_\n";
} else {
print "Unexpected error connecting to $_: $!\n";
}
}
alarm(0);
if (#Results) {
print join("\t", #Results, "\n");
}
}
exit;
The parmfile.mqsc is any valid MQSC script. One that gathers all the queue depths looks like this:
DISPLAY QL(*) CURDEPTH
I think the real problem is that the r(o)sh cmd only executes the remote envscripts.ksh file and that your script is then trying to execute qdisplay on your local machine.
You need to 'glue' the two commands together so they are both executed remotely.
EDITED per comment from Gilles (He is correct)
rosh -n ${server} -l mquser ". /opt/hd/ca/scripts/envscripts.ksh ; qdisplay"
I hope this helps.
P.S. as you appear to be a new user, if you get an answer that helps you please remember to mark it as accepted, or give it a + (or -) as a useful answer