I want to be able to switch on a computer using Linux Bash. Is there a way?
I know to switch off by use of such command as $(init 0) within a bash script
$(init 0)
You can use a wake-on-lan tool, passing the MAC address of the machine to start as an argument.
See: Bash one-line command to send wake on LAN magic packet without specific tool
Its doable in Mac (below), but a bit tricky on Linux. Best bet is to enter into the BIOS by hitting "F2" after you have switched your machine on and find the "Auto Power On" command ... but no scripting.
In Mac OS X bash its part of the "sudo systemsetup" command and could be achieved via "-setharddisksleep minutes" and you can even schedule it via crontab -e, but only as root user. To be honest in Mac its easier to just go to "Energy Saver" and set "Schedule" ... but no scripting.
Related
I need to emulate a terminal in go. I try to do it like this:
lsCmd := exec.Command("bash", "-c", "ls")
lsOut, err := lsCmd.Output()
if err != nil {
panic(err)
}
fmt.Println(string(lsOut))
And it seems to work correctly (the native ubuntu terminal displays a horizontal list, and the result of this function goes vertically).
But if I specifically call the wrong command, for example exec.Command ("bash", "-c", "lss"), I get:
panic: exit status 127
And in the native ubuntu terminal I get the following result:
Command 'lss' not found, did you mean:
and enumeration of commands.
I need to communicate with the native terminal, and get the same thing as the result of the command if I wrote the command in the standard ubuntu terminal.
What is the best way to do this? Maybe the exec library is not suitable for this? All this is necessary for front-end communication with the OS terminal. On a simple html/css/js page, the user enters a command, after go it sends it to the native terminal of the operating system and returns the result to the front-end.
How I can get the same result of executing commands as if I were working in a native terminal?
The problem
But if I specifically call the wrong command, for example exec.Command
("bash", "-c", "lss"), I get:
panic: exit status 127
And in the native ubuntu terminal I get the following result:
Command 'lss' not found, did you mean:
and enumeration of commands.
This has nothing to do with Go, and the problem is actually two-fold:
Ubuntu ships with a special package, command-not-found, which is usually preinstalled, which tries make terminal more friently for mere mortals by employing two techniques:
It tries to suggest corrections for misspellings (your case).
It tries to suggest packages to install when the user tries to execute a program which would have been be available if the user had a specific package installed.
When the command is not found, "plain" (see below) shell fails the attempt by returning a non-zero exit code.
This is absolutely expected and normal.
I mean, panicking on it is absolutely unwise.
There's a historical difference on how a shell is run on a Unix system.
When a user logs into the system (remember that back in the days the concept of the shell was invented you'd be logging in via a hardware computer terminal which was basically what your GNOME Terminal window is but in hardware, and connected over a wire),
the so-called login shell is started.
The primary idea of a logic shell is to provide interactive environment for the user.
But as you surely know, shells are also capable of executing scripts.
When a shell executes a script, it's running in a non-interactive mode.
The modes a Unix shell can work in
Now let's dig deeper into that thing about interactive vs non-interactive shells.
In the interactive mode:
The shell is usually connected to a real terminal (either hadrware or a terminal emulator; your GNOME Terminal window is a terminal emulator).
"Connected" means that the shell's standard I/O streams are connected to the terminal, so that what the shell prints is displayed by the terminal.
It enables certain bells and whistles for the user, usually providind limited means for editing what is being input (bash, for instance, engages GNU readline.
In the non-interactive mode:
The shell's standard I/O streams are connected to some files (or to "nowhere" — like /dev/null).
No bells and whistles are enabled — as there is nobody to make use of them.
GNU bash is able to run in both modes, and which mode it runs in depends
on how it was invoked.
When initializing in different modes, bash reads different initialization scripts, and this explains why the machinery provided by the command-not-found package gets engaged in the interactive mode and does not when bash is run otherwise — like in your invocation from Go.
What do do about the problem
The simplest thing to try is to run bash with the --login command-line option or otherwise make it think it runs as an interactive shell.
This might solve the problem for your case but not necessarily.
The next possible problem is that some programs do really check whether they're running at a terminal — usually these are programs which insist on real interaction with the user, usually for security purposes, and there are programs which simply cannot run when not connected to a real terminal — these are "full-screen" text UI programs such as GNU Midnight Commander, Vim, Emacs, GNU Nano and anything like this.
To solve this problem, the only solution is to run the shell in a pseudo-terminal environment, and that's what #eudore hinted at in their comment.
The github.com/creack/pty might be a package to start looking at; golang.org/x/crypto/ssh also provides some means to wrangle PTYs.
I just recently found out about using bash in windows. I had alot of fun installing linux programs onto my windows computer using bash and wondered how I would be able to run an automatic script so I dont have to export my display everytime I open bash.
I used to write scripts for cmd called batch scripting and I would be able to do everything cmd could do. Now that I have access to bash, I want to script a program that connects useful pieces of cmd with useful pieces of bash but I Can't find any results telling me how to call bash commands from cmd. Thank you - Zak Kaioken
I want to create my own personal logfile that logs not only when I log in and out, but also when I lock/unlock my screen. Kindof like /var/log/wtmp on steroids.
To do this, I decided to run a script when I log into Ubuntu that runs in the background until I quit. My plan to do this is to add the script to .bashrc, using ./startlogging.sh & and in the script I will use trap to catch signals. That's great, except .bashrc gets run every time I open a new terminal, which is not what I want for the logger.
Is there a way to tell in Bash that the current login is a gnome login? Alternatively, is there some sort of .gnomerc I can use to run my script?
Edit: Here is my script:
Edit 2: Removed the script, since it's not related to the question. I will repost my other question, rather than repurpose this one.
Are you looking for a way to detect what type of terminal it is?
Try:
echo $TERM
From Wikipedia:
TERM (Unix-like) - specifies the type of computer terminal or terminal
emulator being used (e.g., vt100 or dumb).
See also: List of Terminal Emulators
for bash use : ~/.bash_logout
that will get executed when you logout, which sounds like what you are trying to do.
Well, for just bash, what you want are .bash_login/.bash_logout in your home directory (rather than .bashrc) These are run whenever a LOGIN shell starts/finishes, which happens any time you log in to a shell (on a tty or console, or via ssh or other network login). These are NOT run for bash processes created to run in terminal windows that you create (as those are not login shells) so won't get run any time you open a new terminal.
The problem is that if you log in with some mechanism that does not involve a terminal (such as gdm running on the console to start a gnome or kde or unity session), then there's no login shell so .bash_login/logout never get run. For that case, the easiest is probably to put something in your .xsessionrc, which will get run every time you start an X session (which happens for any of those GUI environments, regardless of which one you run). Unfortunately, there's no standard script that runs when an X session finishes.
I was wondering if one can open shell of machines accessible by ssh. If I do M-x remote shell, I am taken to the shell on the current machine. In my case, I run emacs over windows XP and therefore it takes me to shell of windows
Let me know if ssh.el works for you?
I'm in a class that uses an implementation of Emacs on a school server. I'm on a mac running snow leopard, and I have my own implementation of Emacs on it. To access the server-Emacs, I ssh into the server and launch Emacs from its location there.
I'm relativly new to emacs, and I have a particular problem whenever I try to access the server-emacs from my local-emacs' shell-mode, having ssh'd into the server. It gives me the error that "Screen size -1x80 is too small", and doesn't launch the server-emacs.
I've the separate issue that when I try to do this in Apple's terminal, it does launch the server-emacs, but I really, really dislike the interface when emacs is launched within a terminal.
I've tried a couple of times to launch the server-emacs within a new window, in both scenarios, but apparently I'm not doing it right.
I think it'd be useful to understand what you're trying to do.
Do you just want to edit files on the server? If that's the case, read the documentation for tramp, and try:
C-x C-f //user#server:/path/to/file
If you really want to use the emacs running on the server, try creating a frame on your
(if so, look up tramp) If you want to actually use the emacs from the server, but have the window display on your mac:
ssh server
setenv DISPLAY mymac:0
emacsclient file &
This does assume you're running X11, and know how to resolve the display for your Mac. You can get X11 for the Mac here.
It's a bit hard to tell what you are doing, but you probably want to ssh to the server with an X tunnel, then run emacs there which will pop up the window on your mac.
First, don't use Terminal.
On your mac, start up X11 (google for XQuartz if you don't already have it).
Start up an XTerm (it should do this by default). From that XTerm, ssh to your server with the -Y option:
ssh -Y me#server.something
This should get you a remote shell and setup the DISPLAY environment to tunnel right back to your Mac's X server. Test it by running an xterm from there. If that works, you can instead run emacs. If that works, you can combine it with the ssh invocation:
ssh -Y me#server.something /usr/bin/emacs # or whatever path you need
You should set up ssh to not require a password but that's more than you asked for.
I think that Trey Jackson's suggestion of tramp (or the more old-fashioned 'ange-ftp) is probably your best bet.
In general, running emacs inside an emacs is never a good idea. You either want to run emacs on the server (in -nw mode inside the terminal, or via some $DISPLAY magic) or run it on your mac (via tramp). There isn't really a good way to do both.