I do a fair bit of work at the command line. When I start my computer up on of the first things I do is open up a terminal window for mysql, and one for the Rails console and usually a third running mongrel. Setting it up every morning is a bit of a drag so I would like to script it. How can I open a terminal window, log into mysql, select my development database and then leave it there at the mysql prompt waiting for me. I know how to execute a mysql statement from bash, I just don't know how to get it to leave the prompt open for me to work with after.
Hopefully that is clear!
Update:
Combining the two answers below got things working for mysql. Thanks!
Now I am trying to get a gnome-terminal window to stay open running the Rails script/server command so I can watch the output. For some reason the following closes almost immediately:
gnome-terminal -e "ruby /home/mike/projects/myapp/script/server" &
xterm provides an option for executing a command:
xterm -e myCommandToLogIntoMysql &
You can put a sequence of such xterm commands into a shell script.
How can I open a terminal window, log
into mysql, select my development
database and then leave it there at
the mysql prompt waiting for me.
mysql -u user -ppassword -D database_name
Remember not to put space between "-p" and password. Note - this is a bit insecure, as your password is visible in process list so anyone can read it using ps. You can, however, put your MySQL password in ~/.my.cnf file.
Related
I just wrote my first bash script to start some redis instances on a development server. While it is mostly working, the last opened redis instance is blocking the active terminal – though I have the trailing & sign and the other started instances aren't blocking the terminal. How would I push them all to the background?
Here's the script:
#!/bin/bash
REDIS=(6379 6380 6381 6382 6383 6390 6391 6392 6393)
for i in "${REDIS[#]}"
do
:
redis-server --port $i &
done
It sounds like your terminal is not actually blocked, your prompt just got overwritten. It's a purely cosmetic issue. Due to the way terminals work, bash doesn't know to redraw it so it looks like the command is in the foreground.
Run the script again, and blindly type lsEnter. You'll probably see that the shell responds as normal, even though you can't see the prompt.
You can alternatively just hit Enter to get bash to redraw the prompt.
I got stuck in this problem. I need to run two commands in shell script, but they can't stop each other.
For example, this shell script:
psql database user &
gedit file
If I run these commands up, only the gedit process stays open and I can't see where the process of psql is.
But if I do this:
gedit file &
psql database user
I can see the psql's process, but it's closed by messages of gedit's process.
How can I execute this script without one process close the other?
If you want to suppress output from gedit:
gedit file >/dev/null 2>&1 &
psql database user
However, the claim:
I can see the psql's process, but it's closed by messages of gedit's process.
...simply doesn't happen: Messages from gedit go directly to the terminal; psql can't see them, so it can't possibly be exiting because of them.
What's the best way to run this shell script where I need to create an output log at the same time run it in the background? The catch is, I need to input a couple of parameters then enter a password.
For example I execute the shell script like so:
-bash-4.3$ ./tst.sh param1 param2 >> tst.log
Password for user mas:
I need to pass in (2) parameters, then prompted for a password:
./tsh.sh <param1> <param2>
This will work, but I have to keep the session open and I want it so it goes to the background or something similar where it will continue to run if my connection to the host fails..
If you want to run something that will survive if your connection fails you should run it in a screen or tmux session. You can use those to create sessions that you can disconnect from and reconnect to, and many other really cool things once you start really getting into them.
So if you ssh in and then run screen you'll still be at a bash prompt, but if you run a command then press ^a^d you will detach from that session. Everything running inside screen will keep going, and you'll be able to reconnect with screen -x later. You can have many screen sessions at the same time too, use screen -ls to see which are running then you can use screen -x <id> to reconnect to a particular one.
I am using elastic map reduce from Amazon. I am sshing into hadoop master node and executing a script like.
$EMR_BIN/elastic-mapreduce --jobflow $JOBFLOW --ssh < hivescript.sh . It sshes me into the master node and runs the hive script. The hivescript contains the following lines
hive
add jar joda-time-1.6.jar;
add jar EmrHiveUtils-1.2.jar;
and some commands to create hive tables. The script runs fine and creates the hive tables and everything else, but comes back to the prompt from where I ran the script. How do I leave it sshed into hadoop master node at the hive prompt.
Consider using Expect, then you could do something along these lines and interact at the end:
/usr/bin/expect <<EOF
spawn ssh ... YourHost
expect "password"
send "password\n"
send javastuff
interact
EOF
These are the most common answers I've seen (with the drawbacks I ran into with them):
Use expect
This is probably the most well rounded solution for most people
I cannot control whether expect is installed in my target environments
Just to try this out anyway, I put together a simple expect script to ssh to a remote machine, send a simple command, and turn control over to the user. There was a long delay before the prompt showed up, and after fiddling with it with little success I decided to move on for the time being.
Eventually I came back to this as the final solution after realizing I had violated one of the 3 virtues of a good programmer -- false impatience.
Use screen / tmux to start the shell, then inject commands from an external process.
This works ok, but if the terminal window dies it leaves a screen/tmux instance hanging around. I could certainly try to come up with a way to just re-attach to prior instances or kill them; screen (and probably tmux) can make it die instead of auto-detaching, but I didn't fiddle with it.
If using gnome-terminal, use its -x or --command flag (I'm guessing xterm and others have similar options)
I'll go into more detail on problems I had with this on #4
Make a bash script with #!/bin/bash --init-file as the shebang; this will cause your script to execute, then leave an interactive shell running afterward
This and #3 had issues with some programs that required user interaction before the shell is presented to them. Some programs (like ssh) it worked fine with, others (telnet, vxsim) presented a prompt but no text was passed along to the program; only ctrl characters like ^C.
Do something like this: xterm -e 'commands; here; exec bash'. This will cause it to create an interactive shell after your commands execute.
This is fine as long as the user doesn't attempt to interrupt with ^C before the last command executes.
Currently, the only thing I've found that gives me the behavior I need is to use cmdtool from the OpenWin project.
/usr/openwin/bin/cmdtool -I 'commands; here'
# or
/usr/openwin/bin/cmdtool -I 'commands; here' /bin/bash --norc
The resulting terminal injects the list of commands passed with -I to the program executed (no parms means default shell), so those commands show up in that shell's history.
What I don't like is that the terminal cmdtool provides feels so clunky ... but alas.
I am new to Ubuntu and Bash scripting. I am working on a project to give a demo on an SDN application to my class. I need some help in scripting to create the demo. Please help in case if you have any idea on what am asking.
The demo uses a tool called mininet. I need just one script so that I can automate the whole of my demo.
The commands I need to run are given in order below.
Run "sudo mn" on the terminal. This changes the prompt from
/mininet$ sudo mn
to
mininet>
Now on this terminal where the prompt is mininet>, I need to run xterm h1 followed by xterm h2 to create separate terminals for two hosts created by mininet.
I have to access the xterm terminal for h1 and run a command there . eg: ifconfig
I have to access the xterm terminal for h2 and run a command there . eg : set ip address
I have to run a ping in xterm terminal for h1 and while this is happening, i want to access terminals of h2 and start a ping in xterm terminals of h2.
I have to go back to the previous terminal from where the xterm terminals were spawned. mininet> prompt one. and run exit and then when the prompt goes back to normal /mininet$ i have to sudo mn -c.
All of this should be done from one script. Please ignore the specific commands mentioned and give a generic solution or clues.