This question already has answers here:
how do i start commands in new terminals in BASH script
(2 answers)
Closed 20 days ago.
So i want to open a new terminal in bash and execute a command with arguments.
As long as I only take something like ls as command it works fine, but when I take something like route -n , so a command with arguments, it doesnt work.
The code:
gnome-terminal --window-with-profile=Bash -e whoami #WORKS
gnome-terminal --window-with-profile=Bash -e route -n #DOESNT WORK
I already tried putting "" around the command and all that but it still doesnt work
You can start a new terminal with a command using the following:
gnome-terminal --window-with-profile=Bash -- \
bash -c "<command>"
To continue the terminal with the normal bash profile, add exec bash:
gnome-terminal --window-with-profile=Bash -- \
bash -c "<command>; exec bash"
Here's how to create a Here document and pass it as the command:
cmd="$(printf '%s\n' 'wc -w <<-EOF
First line of Here document.
Second line.
The output of this command will be '15'.
EOF' 'exec bash')"
xterm -e bash -c "${cmd}"
To open a new terminal and run an initial command with a script, add the following in a script:
nohup xterm -e bash -c "$(printf '%s\nexec bash' "$*")" &>/dev/null &
When $* is quoted, it expands the arguments to a single word, with each separated by the first character of IFS. nohup and &>/dev/null & are used only to allow the terminal to run in the background.
Try this:
gnome-terminal --window-with-profile=Bash -e 'bash -c "route -n; read"'
The final read prevents the window from closing after execution of the previous commands. It will close when you press a key.
If you want to experience headaches, you can try with more quote nesting:
gnome-terminal --window-with-profile=Bash \
-e 'bash -c "route -n; read -p '"'Press a key...'"'"'
(In the following examples there is no final read. Let’s suppose we fixed that in the profile.)
If you want to print an empty line and enjoy multi-level escaping too:
gnome-terminal --window-with-profile=Bash \
-e 'bash -c "printf \\\\n; route -n"'
The same, with another quoting style:
gnome-terminal --window-with-profile=Bash \
-e 'bash -c '\''printf "\n"; route -n'\'
Variables are expanded in double quotes, not single quotes, so if you want them expanded you need to ensure that the outermost quotes are double:
command='printf "\n"; route -n'
gnome-terminal --window-with-profile=Bash \
-e "bash -c '$command'"
Quoting can become really complex. When you need something more advanced that a simple couple of commands, it is advisable to write an independent shell script with all the readable, parametrized code you need, save it somewhere, say /home/user/bin/mycommand, and then invoke it simply as
gnome-terminal --window-with-profile=Bash -e /home/user/bin/mycommand
In a bash script I start a new terminal with a command that gives an error. However I don't seem to be able to grab that error code:
#! /bin/bash
gnome-terminal -x bash -c "cat dksdamfasdlm"
echo $?
Output:
0
So I get the error code of the gnome-terminal command instead of the cat one. One suggestion I got, was to make a file with the code and read that from the parent bash. The problem is that I still seem to not be able and read the error code even that way:
#! /bin/bash
gnome-terminal -x bash -c "cat dksdamfasdlm; echo $?; sleep 2"
Output (on new terminal):
cat: dksdamfasdlm: No such file or directory
0
Why is that? Some suggestion on how to solve this? I just want to somehow grab the error in the new terminal from the parent bash.
It seems GNOME Terminal exits immediately after starting, which is obvious if you run for example gnome-terminal -x sleep 10. Since it doesn't wait for the command to finish, there's no way the return code will be that of the command. I could find no option in gnome-terminal --help-all to keep the process in the foreground.
Regarding your second question, you've double-quoted the command, so $? is expanded before running it. This should work:
gnome-terminal -x bash -c 'cat dksdamfasdlm; echo $?; sleep 2'
PS: The -x option is not documented in GNOME Terminal 3.8.4's gnome-terminal --help-all, various references don't help much, and there's no good explanation for why there's a -e option with identical semantics and different syntax.
I already know how to open a terminal in a bash with gnome-terminal and execute a program:
gnome-terminal -e ./OpenBTSCLI
But I also need that once open that program in the new terminal, write another command inside.
When a I tried to use echo, the message appear in the terminal where I run the bash.
I tried: gnome-terminal -e "bash -c './OpenBTSCLI && echo message'" that I find online but its not working, it only do the first part.
Anyone have an idea of how to resolve this? Thank you
I think it does the second command as well, but the new terminal closes as soon as the command's finished, so you don't see it. I reversed the order of quotes and added a 1s sleep at the end to allow seeing the echo.
gnome-terminal -e 'bash -c "./OpenBTSCLI && echo message && sleep 1"'
I want an advanced shell or command line in Unix which has the following features:
output to err and out are in different colours.
I should be able to highlight (or find) keywords in the output of the executing command.
indicator in the OS task-bar/title as a command is running or completed.
I am looking at an advanced shell that boosts productivity. Is there any alternative?
Re: output to err and out are in different colours ... can be done in Bash.
# colourize stderr in current shell
# note: use sed in line-buffering mode
(
exec 2> >(sed -l -e $'s/.*/\033[31m&\033[m/')
ls -ld / xxxxx
)
# colourize stderr & stdout in current shell
(
exec 1> >(sed -l -e $'s/.*/\033[32m&\033[m/') 2> >(sed -l -e $'s/.*/\033[31m&\033[m/')
ls -ld / xxxxx
)
That isn't a trivial proposition.
There are shells that work with the terminal to echo the currently executing command in the title bar, such as bash on MacOS X.
The commands are autonomous and do not, in general, colour-code their output. So, to get colour-coded output, the shell will have to capture the error outputs of the commands it runs, and arrange to display that information appropriately colour-coded.
Searching the output requires the terminal program to keep the output it displays in a searchable form, and some program (probably the terminal program or possibly the shell) will have to respond to searching operations.
Emacs allows you to run interactive shells such as bash or zsh.
rc works similarly when run in Plan9 -- I'm not sure about its Unix ports.
This is a follow-on question to the How do you use ssh in a shell script? question. If I want to execute a command on the remote machine that runs in the background on that machine, how do I get the ssh command to return? When I try to just include the ampersand (&) at the end of the command it just hangs. The exact form of the command looks like this:
ssh user#target "cd /some/directory; program-to-execute &"
Any ideas? One thing to note is that logins to the target machine always produce a text banner and I have SSH keys set up so no password is required.
I had this problem in a program I wrote a year ago -- turns out the answer is rather complicated. You'll need to use nohup as well as output redirection, as explained in the wikipedia artcle on nohup, copied here for your convenience.
Nohuping backgrounded jobs is for
example useful when logged in via SSH,
since backgrounded jobs can cause the
shell to hang on logout due to a race
condition [2]. This problem can also
be overcome by redirecting all three
I/O streams:
nohup myprogram > foo.out 2> foo.err < /dev/null &
This has been the cleanest way to do it for me:-
ssh -n -f user#host "sh -c 'cd /whereever; nohup ./whatever > /dev/null 2>&1 &'"
The only thing running after this is the actual command on the remote machine
Redirect fd's
Output needs to be redirected with &>/dev/null which redirects both stderr and stdout to /dev/null and is a synonym of >/dev/null 2>/dev/null or >/dev/null 2>&1.
Parantheses
The best way is to use sh -c '( ( command ) & )' where command is anything.
ssh askapache 'sh -c "( ( nohup chown -R ask:ask /www/askapache.com &>/dev/null ) & )"'
Nohup Shell
You can also use nohup directly to launch the shell:
ssh askapache 'nohup sh -c "( ( chown -R ask:ask /www/askapache.com &>/dev/null ) & )"'
Nice Launch
Another trick is to use nice to launch the command/shell:
ssh askapache 'nice -n 19 sh -c "( ( nohup chown -R ask:ask /www/askapache.com &>/dev/null ) & )"'
If you don't/can't keep the connection open you could use screen, if you have the rights to install it.
user#localhost $ screen -t remote-command
user#localhost $ ssh user#target # now inside of a screen session
user#remotehost $ cd /some/directory; program-to-execute &
To detach the screen session: ctrl-a d
To list screen sessions:
screen -ls
To reattach a session:
screen -d -r remote-command
Note that screen can also create multiple shells within each session. A similar effect can be achieved with tmux.
user#localhost $ tmux
user#localhost $ ssh user#target # now inside of a tmux session
user#remotehost $ cd /some/directory; program-to-execute &
To detach the tmux session: ctrl-b d
To list screen sessions:
tmux list-sessions
To reattach a session:
tmux attach <session number>
The default tmux control key, 'ctrl-b', is somewhat difficult to use but there are several example tmux configs that ship with tmux that you can try.
I just wanted to show a working example that you can cut and paste:
ssh REMOTE "sh -c \"(nohup sleep 30; touch nohup-exit) > /dev/null &\""
You can do this without nohup:
ssh user#host 'myprogram >out.log 2>err.log &'
Quickest and easiest way is to use the 'at' command:
ssh user#target "at now -f /home/foo.sh"
I think you'll have to combine a couple of these answers to get what you want. If you use nohup in conjunction with the semicolon, and wrap the whole thing in quotes, then you get:
ssh user#target "cd /some/directory; nohup myprogram > foo.out 2> foo.err < /dev/null"
which seems to work for me. With nohup, you don't need to append the & to the command to be run. Also, if you don't need to read any of the output of the command, you can use
ssh user#target "cd /some/directory; nohup myprogram > /dev/null 2>&1"
to redirect all output to /dev/null.
This worked for me may times:
ssh -x remoteServer "cd yourRemoteDir; ./yourRemoteScript.sh </dev/null >/dev/null 2>&1 & "
You can do it like this...
sudo /home/script.sh -opt1 > /tmp/script.out &
It appeared quite convenient for me to have a remote tmux session using the tmux new -d <shell cmd> syntax like this:
ssh someone#elsewhere 'tmux new -d sleep 600'
This will launch new session on elsewhere host and ssh command on local machine will return to shell almost instantly. You can then ssh to the remote host and tmux attach to that session. Note that there's nothing about local tmux running, only remote!
Also, if you want your session to persist after the job is done, simply add a shell launcher after your command, but don't forget to enclose in quotes:
ssh someone#elsewhere 'tmux new -d "~/myscript.sh; bash"'
Actually, whenever I need to run a command on a remote machine that's complicated, I like to put the command in a script on the destination machine, and just run that script using ssh.
For example:
# simple_script.sh (located on remote server)
#!/bin/bash
cat /var/log/messages | grep <some value> | awk -F " " '{print $8}'
And then I just run this command on the source machine:
ssh user#ip "/path/to/simple_script.sh"
If you run remote command without allocating tty, redirect stdout/stderr works, nohup is not necessary.
ssh user#host 'background command &>/dev/null &'
If you use -t to allocate tty to run interactive command along with background command, and background command is the last command, like this:
ssh -t user#host 'bash -c "interactive command; nohup backgroud command &>/dev/null &"'
It's possible that background command doesn't actually start. There's race here:
bash exits after nohup starts. As a session leader, bash exit results in HUP signal sent to nohup process.
nohup ignores HUP signal.
If 1 completes before 2, the nohup process will exit and won't start the background command at all. We need to wait nohup start the background command. A simple workaroung is to just add a sleep:
ssh -t user#host 'bash -c "interactive command; nohup backgroud command &>/dev/null & sleep 1"'
The question was asked and answered years ago, I don't know if openssh behavior changed since then. I was testing on:
OpenSSH_8.6p1, OpenSSL 1.1.1g FIPS 21 Apr 2020
I was trying to do the same thing, but with the added complexity that I was trying to do it from Java. So on one machine running java, I was trying to run a script on another machine, in the background (with nohup).
From the command line, here is what worked: (you may not need the "-i keyFile" if you don't need it to ssh to the host)
ssh -i keyFile user#host bash -c "\"nohup ./script arg1 arg2 > output.txt 2>&1 &\""
Note that to my command line, there is one argument after the "-c", which is all in quotes. But for it to work on the other end, it still needs the quotes, so I had to put escaped quotes within it.
From java, here is what worked:
ProcessBuilder b = new ProcessBuilder("ssh", "-i", "keyFile", "bash", "-c",
"\"nohup ./script arg1 arg2 > output.txt 2>&1 &\"");
Process process = b.start();
// then read from process.getInputStream() and close it.
It took a bit of trial & error to get this working, but it seems to work well now.
YOUR-COMMAND &> YOUR-LOG.log &
This should run the command and assign a process id you can simply tail -f YOUR-LOG.log to see results written to it as they happen. you can log out anytime and the process will carry on
If you are using zsh then use program-to-execute &! is a zsh-specific shortcut to both background and disown the process, such that exiting the shell will leave it running.
A follow-on to #cmcginty's concise working example which also shows how to alternatively wrap the outer command in double quotes. This is how the template would look if invoked from within a PowerShell script (which can only interpolate variables from within double-quotes and ignores any variable expansion when wrapped in single quotes):
ssh user#server "sh -c `"($cmd) &>/dev/null </dev/null &`""
Inner double-quotes are escaped with back-tick instead of backslash. This allows $cmd to be composed by the PowerShell script, e.g. for deployment scripts and automation and the like. $cmd can even contain a multi-line heredoc if composed with unix LF.
First follow this procedure:
Log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:
a#A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a#A
Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):
a#A:~> ssh b#B mkdir -p .ssh
b#B's password:
Finally append a's new public key to b#B:.ssh/authorized_keys and enter b's password one last time:
a#A:~> cat .ssh/id_rsa.pub | ssh b#B 'cat >> .ssh/authorized_keys'
b#B's password:
From now on you can log into B as b from A as a without password:
a#A:~> ssh b#B
then this will work without entering a password
ssh b#B "cd /some/directory; program-to-execute &"
I think this is what you need:
At first you need to install sshpass on your machine.
then you can write your own script:
while read pass port user ip; do
sshpass -p$pass ssh -p $port $user#$ip <<ENDSSH1
COMMAND 1
.
.
.
COMMAND n
ENDSSH1
done <<____HERE
PASS PORT USER IP
. . . .
. . . .
. . . .
PASS PORT USER IP
____HERE