How can I check if a command can be successfully executed without actually executing it? For example, if i want to connect to another host using telnet connection, how do i check if telnet client exists or not? Or if I want to do a cp or mkdir or rmdir, how do I check if any of these commands can be valid before executing them?
You can always run
which telnet
this will tell you the actual file that would be executed. However, it will not tell you if the command will run with success. For instance, which cp will only tell you where the executable is and not if the files being copied exist and you have the right to copy them to the chosen destination.
Hope this helps
Related
I have some scripts that I run using jboss-cli -c --controller=... --file=myscript.cli.
The -c and --controller options are great, because my script does not know which server it should be run against and can be reused for multiple servers.
I now want to use the offline-cli feature to avoid port conflicts and prevent servers from beeing reachable through the network while they are beeing set up.
My issue is now that in order to start an embedded server I have to use the CLI-command embed-server, but I don't want to add that command to my scripts, because the scripts are not supposed to know the name of the server config xml file.
Unfortunately I can't use both --command="embed-server --server-config=my-standalone.xml" and --file=myscript.cli at the same time, because the CLI complains with:
Only one of '--file', '--commands' or '--command' can appear as the argument at a time.
Another thing I tried was: --commands="embed-server --server-config=my-standalone.xml,run-batch --file=\"myscript.cli\" but this does not work either, because my scripts contain some if-else logic, for instance:
if (outcome == success) of /subsystem=iiop-openjdk:read-resource()
/subsystem=iiop-openjdk:remove()
end-if
And unfortunately conditional logic is not supported in batch mode (see https://bugzilla.redhat.com/show_bug.cgi?id=1083176).
the simple way is to start your embedded server in your script :
embed-server --std-out=echo --server-config=standalone-full.xml
/subsystem=messaging-activemq/server=default/jms-queue=inQueue:add(durable=true, entries=["/queue/inQueue","java:jboss/exported/queue/inQueue"])
/subsystem=messaging-activemq/server=default/jms-queue=outQueue:add(durable=true, entries=["/queue/outQueue","java:jboss/exported/queue/outQueue"])
quit
Don't forget to quit at the end of your cli script :)
If you are using a Unix system you may try something like this:
(echo embed-server --std-out=echo --server-config=my-standalone.xml; cat myscript.cli) | jboss-cli.sh
I have to take quite a few steps before I get into the file I need to be, which is why I'm trying to set up an alias in my terminal, that gets me to the file by running that alias.
The following steps are needed to arrive where I have to be:
cd Sites
vagrant ssh
cd /var/www/miniportal.billetten.dk/logs/
sudo -s
cd /etc/apache2/sites-available/
nano 25-av_miniportal.conf
Edit line 33 in that file (I guess it's possible to jump to that line)
I tried setting up an alias like this, but the problem is that it stops running the rest of the command after I SSH'd into Vagrant. if I manually exit Vagrant, it continues the command (and of course returns an error, because there is no such folder).
The question is: How do I make sure that everything from step 3 is executed AFTER step 2 is done logging in through SSH?
My ultimate goal is to set up an Apple Automator program that lets me put in a value that gets entered on line 33, but I'm fine with just an alias for now.
I know I asked this question a long time ago, but in the meantime I found a solution and forgot I had posted this question.
My alias in my .zshrc-file looks like this:
alias changeCust='ssh -t root#192.168.56.101 "nano +32 /etc/apache2/sites-enabled/25-av_miniportal.conf && service apache2 reload"'
In other words, it SSHs into vagrant as root (it asks for my password), nanos into a file on line 32 (or whatever line you need), then, when the file is saved, it reloads apache2 and the changes are applied.
Just use the below one and change the values.
alias AliasName='ssh -t root#your.ip.addres.here "nano +lineNumber /path/to/file"'
Is there any way to save the PuTTY output to a file using the command line? I know this is easily done using the GUI but in my case it has to be done automatically.
What I'm working on:
User clicks batch file -> starts PuTTY, automatically connects to my device over SSH and runs a bunch of commands -> PuTTY should save the output to a file.
The last part I can't get working. Is there any command to do this?
This can be done with putty. The answer is little late considering the time the questions was asked, however this might help someone.
In putty, using GUI, you can save sessions with logging option on, as shown below.
Enter Host Name, Name the session, Go to Logging Option in the left top corner, select all sessions, provide log file name and location, go back to Session tab, click on the save button. Done, you have saved a session.
Now open CMD and write the command as below
You are done. Every time this session is invoked, the commands and output will be logged.
Hope this helps.
The specific program putty is not designed for this. Instead use plink, a different program in the PuTTY suite,
which uses the same session settings and keys as putty but gets input from stdin and puts output to stdout,
both of which can be redirected in the usual ways. See http://the.earth.li/~sgtatham/putty/0.63/htmldoc/Chapter7.html#plink .
As mentioned in previous answer, use plink for this.
Make sure it is in your environment path, by typing
plink -V
in your console. If it returns a version number, then you know it is in environment path variables. If it doesn't, probably best to fix this first. There are plenty of good SO answers to help you with this. Failing that, use the full path to your plink.exe in the CLI command that follows.
Then use plink to open your ssh connection, with the option -v set to provide verbose output. Finally, this all needs to be piped to a log file.
The complete cli command that I use is
plink -v username#xxx.xxx.xxx.xxx > ssh-output.log 2>&1
Open up the file ssh-ouput.log to see the results.
Expanding on Dave's and Charlie's answers...
Apart from making sure plink is in the path, also check whether you have write access to local ouput file.
This is how you redirect command output from remote machine to local file with plink. In this example we store an output from man page for nfcapd:
plink joe#192.168.50.50 -pw joespassword man nfcapd > output.log 2>&1
The first time you try to access the server, it will ask you store key in cache. So make sure to access the machine at least once before:
plink joe#192.168.50.50 -pw joespassword
The server's host key is not cached in the registry. You
have no guarantee that the server is the computer you
think it is.
...
Store key in cache? (y/n)
I'm trying to dump DHCP settings from an older server thats being decommissioned. I ran the command fine while on the actual server but when trying to run it using psexec remotely, it keeps failing. The command is: psexec \\$source netsh dhcp server \\$source dump>$dhcpSettings
$source = the server being decommissioned
$dhcpSettings = the path to save the dumped settings
I've tried all sorts of combinations of encapsulating quotation marks but still nothing. the errors I'm getting is, "The system cannot find the file specified" and "The system cannot find the path specified"
EDIT: So I got rid of the path to save the dumped settings and now it works. But how should I format the command so that it'll save the settings to the remote computer's C:\USER.SET\LOG directory?
One solution might be to bundle the command you want to run and the stdout redirection into a single line cmd file and use PsExec -c or -f to copy and execute that file on the remote system. As an example
Create a line cmd file named DHCPSettings.cmd with the following in it and save it to C:\temp\:
netsh dhcp server \\localhost dump >c:\user.set\log\dhcpsetting.log
Then use
psexec \\$source -c c:\temp\DHCPSettings.cmd
You did not really provide any code to go by and I am not sure I understand the all requirements and constraints you have, so consider this as an idea; not the exact commands you need to run. Hope it helps.
Is it possible to have a Perl script run shell aliases? I am running into a situation where we've got a Perl module I don't have access to modify and one of the things it does is logs into multiple servers via SSH to run some commands remotely. Sadly some of the systems (which I also don't have access to modify) have a buggy SSH server that will disconnect as soon as my system tries to send an SSH public key. I have the SSH agent running because I need it to connect to some other servers.
My initial solution was to set up an alias to set ssh to ssh -o PubkeyAuthentication=no, but Perl runs the ssh binary it finds in the PATH instead of trying to use the alias.
It looks like the only solutions are disable the SSH agent while I am connecting to the problem servers or override the Perl module that does the actual connection.
Perhaps you could put a command called ssh in PATH ahead of the ssh which runs ssh as you want it to be run.
Alter the PATH before you run the perl script, or use this in your .ssh/config
Host *
PubkeyAuthentication no
Why don't you skip the alias and just create a shell script called ssh in a directory somewhere, then change the path to put that directory before the one containing the real ssh?
I had to do this recently with iostat because the new version output a different format that a third-party product couldn't handle (it scanned the output to generate a report).
I just created an iostat shell script which called the real iostat (with hardcoded path, but you could be more sophisticated), passing the output through an awk script to massage it into the original format. Then, I changed the path for the third-party program and it started working fine.
You could declare a function in .bashrc (or .profile or whatever) with that name. It could look like this (might break):
function ssh {
/usr/bin/ssh -o PubkeyAuthentication=no "$#"
}
But using a config file might be the best solution in your case.