I have script that access module locally using the code
exec 3<> /dev/tcp/127.0.0.1/5037 ; echo -e "my command here" >&3 ; cat <&3
In the telnet session, I got the lines
Remote connection from 127.0.0.1:51698 to 127.0.0.1:5037
Closing connection to 127.0.0.1:51698
These outputs appears also with telnet sessions (without script)
How can I stop them as the script is running multiple timer per min and is spamming the console?
You can redirect it in a .txt file.
This might help you:
your_command > log.txt 2>&1
This will leave your console clean while all the logs will be saved on log.txt
Related
What is a good way to be able to directly send to STDIN and receive from STDOUT of a process? I'm specifically interested in SSH, as I want to do the following:
[ssh into a remote server]
[run remote commands]
[run local commands]
[run remote commands]
etc...
For example, let's say I have a local script "localScript" that will output the next command I want to run remotely, depending on the output of "remoteScript". I could do something like:
output=$(ssh myServer "./remoteScript")
nextCommand=$(./localScript $output)
ssh myServer "$nextCommand"
But it would be nice to do this without closing/reopening the SSH connection at every step.
You can redirect SSH input and output to FIFO-s and then use these for two-way communication.
For example local.sh:
#!/bin/sh
SSH_SERVER="myServer"
# Redirect SSH input and output to temporary named pipes (FIFOs)
SSH_IN=$(mktemp -u)
SSH_OUT=$(mktemp -u)
mkfifo "$SSH_IN" "$SSH_OUT"
ssh "$SSH_SERVER" "./remote.sh" < "$SSH_IN" > "$SSH_OUT" &
# Open the FIFO-s and clean up the files
exec 3>"$SSH_IN"
exec 4<"$SSH_OUT"
rm -f "$SSH_IN" "$SSH_OUT"
# Read and write
counter=0
echo "PING${counter}" >&3
cat <&4 | while read line; do
echo "Remote responded: $line"
sleep 1
counter=$((counter+1))
echo "PING${counter}" >&3
done
And simple remote.sh:
#!/bin/sh
while read line; do
echo "$line PONG"
done
The method you are using works, but I don't think you can reuse the same connection everytime. You can, however, do this using screen, tmux or nohup, but that would greatly increase the complexity of your script because you will now have to emulate keypresses/shortcuts. I'm not even sure if you can if you do directly in bash. If you want to emulate keypresses, you will have to run the script in a new x-terminal and use xdotool to emulate the keypresses.
Another method is to delegate the whole script to the SSH server by just running the script on the remote server itself:
ssh root#MachineB 'bash -s' < local_script.sh
Why my named pipe input command line just hangs when it is called?
Based on the answers:
Writing to stdin of background process
Accessing bash command line args $# vs $*
Send command to a background process
Can I redirect output to a log file and background a process at the same time?
I wrote two shell scripts to communicate with my game server. And worked the first time I did it. Since it them they do not work anymore. Every time I do ./send.sh commands the command line hangs until I hit Ctrl+C.
It also hangs and does nothing when I do directly echo commamd > /tmp/srv-input
The scripts
It does start the server and configure it to read/receive my commands while it run in background:
start_czero_server.sh
#!/bin/sh
# Go to the game server application folder where the game application `hlds_run` is
cd /home/user/Half-Life
pkill -f hlds
# Set up a pipe named `/tmp/srv-input`
rm /tmp/srv-input
mkfifo /tmp/srv-input
cat > /tmp/srv-input &
echo $! > /tmp/srv-input-cat-pid
# Start the server reading from the pipe named `/tmp/srv-input`
# And also output all its console to the file `/home/user/Half-Life/my_logs.txt`
cat /tmp/srv-input | ./hlds_run -console -game czero +port 27015 > my_logs.txt 2>&1 &
# Successful execution
exit 0
This second script it just a wrapper which allow me easily to send commands to the my server:
send.sh
#!/bin/sh
echo "$#" > /tmp/srv-input
# Successful execution
exit 0
Now every time I want to send a command to my server I just do on the terminal:
./send.sh mp_timelimit 30
I always keep another open terminal open just to listen to my server server console. To do it just use the tail command with the -f flag to follow my server console output:
./tail -f /home/user/Half-Life/my_logs.txt
You would be better off just having hlds_run read directly from the pipe instead of having cat pipe it in.
Try
./hlds_run … > my_logs.txt 2>&1 < /tmp/srv-input &
Instead of
cat /tmp/srv-input | ./hlds_run …
In a very simplified scenario, I have a script that looks like this:
mv test _test
sleep 10
echo $1
mv _test test
and if I execute it with:
ssh localhost "test.sh foo"
the test file will have an underscore in the name as long as the script is running, and when the script is finished, it will send foo back. The script SHOULD keep running, even if you terminate the ssh command by pressing ctrl+c or if you lose connection the the server, but it doesn't (the file is not renamed back to "test"). So, I tried the following:
nohup ssh localhost "test.sh foo"
and it makes ssh immune to ctrl+c but flaky connection to the server still causes trouble. After some debugging, it turns out that the script WILL actually reach the end IF THERE IS NO ECHO IN IT. And when you think about it, it makes sense - when the connection is dropped, there is no more stdout (ssh socket) to echo to, so it will fail, silently.
I can, of course, echo to a file and then get the file, but I would prefer something smarter, along the lines of test tty && echo $1 (but tty invoked like this always returns false). Any suggestions are greatly appreciated.
The following command does what you want:
ssh -t user#host 'nohup ~/test.sh foo > nohup.out 2>&1 & p1=$!; tail -f ~/nohup.out & wait $p1'
... test.sh is located in the users home directory
Explanation:
1.) "ssh -t user#host " ... pretty clear ... starts remote session
2.) "nohup ~/test.sh foo > nohup.out 2>&1" ... starts the test.sh script with nohup in background
3.) "p1=$!;" ... stores the child pid of the previous command in p1
4.) "tail -f ~/nohup.out &" ... tail nohup.out in background to see the output of test.sh
5.) "wait $p1" ... waits for proccess test.sh (which pid is stored in p1) to finish
The above command works even if you interrupt it with ctrl+c.
you can use ...
ssh -t localhost "test.sh foo"
... to force a tty allocation
As st0ne suggested, tail fails, but does not cause the script to terminate, as opposed to cat and echo. So, there is no need for nohup, redirecting stdout to a temporary file, etc. just plain and simple:
mv test _test
sleep 10
echo $1 | tail
mv _test test
and execute it with:
ssh localhost "test.sh foo"
Here is what I'm entering in Terminal:
curl --silent https://raw.githubusercontent.com/githubUser/repoName/master/installer.sh | bash
The WordPress installing bash script contains a "read password" command that is supposed to wait for users to input their MySQL password. But, for some reason, that doesn't happen when I run it with the "curl githubURL | bash" command. When I download the script via wget and run it via "sh installer.sh", it works fine.
What could be the cause of this? Any help is appreciated!
If you want to run a script on a remote server without saving it locally, you can try this.
#!/bin/bash
RunThis=$(lynx -dump http://127.0.0.1/example.sh)
if [ $? = 0 ] ; then
bash -c "$RunThis"
else
echo "There was a problem downloading the script"
exit 1
fi
In order to test it, I wrote an example.sh:
#!/bin/bash
# File /var/www/example.sh
echo "Example read:"
read line
echo "You typed: $line"
When I run Script.sh, the output looks like this.
$ ./Script.sh
Example read:
Hello World!
You typed: Hello World!
Unless you absolutely trust the remote scripts, I would avoid doing this without examining it before executing.
It wouldn't stop for read:
As when you are piping in a way you are forking a child which has been given input from parent shell.
You cannot give the values back to parent(modify parent's env) from child.
and through out this process you are always in parent process.
I am trying to pipe commands to an opened SSH session. The commands will be generated by a script, analyzing the results, and sending the next commands in accordance.
I do not want to put all the commands in a script on the remote host, and just run that script, because I am interested also in the status of the SSH process: sending locally the commands allow to "test" whether the SSH connection is alive or not, and get the appropriate return code from the SSH process.
I tried using something along these lines:
$ mkfifo /tpm/commands
$ ssh -t remote </tmp/commands
And from another term:
$ echo "command" >> /tmp/commands
Problem: SSH tells me that no pseudo-tty will be opened for stdin, and closes the connection as soon as "command" terminates.
I tried another approach:
$ ssh -t remote <<EOF
$(echo "command"; while true; do sleep 10; echo "command"; done)
EOF
But then, nothing is flushed to ssh until EOF is reached (in my case, never).
Do any of you have a solution ?
Stop closing /tmp/commands before you're done with it. When you close the pipe, ssh stops reading from it.
exec 7> /tmp/commands. # open once
echo foo >&7 # write multiple times
echo bar >&7
exec 7>&- # close once
You can additionally use ssh -tt to force ssh to open a tty on the remote.