Executing a command after the first command executed - bash

I just recently installed beep on Ubuntu and finally managed to get it to work.
So I was able to hear the beeping sound after executing:
beep
Everything worked well, however, I was just wondering if it's possible to execute "beep" everytime I execute a command. Say for example:
cat /etc/passwd && beep
After reading /etc/passwd, it will be executing a beeping sound. I'd like to know if there's a way to execute beep after every command without having me to use "&& beep" always.
A clearer example:
ls && beep
ls -la && beep
cat /etc/passwd && beep
Notice the constant command "beep" followed by "&&" after every initial command.

You can set PROMPT_COMMAND=beep (try it first, then add to your ~/.bashrc if it doesn't drive you crazy). This will execute beep just before it displays the command prompt.

You could try altering your prompt:
PS1="$PS1"'\007'

Related

Lua Mac os.execute open Terminal and run command

I need to open the Mac Terminal and run some commands with os.execute in Lua
export VAMP_PATH=/path/to/plugin/directory
cd /path/to/script
./sonic-annotator -l
EDIT: got it to work without terminal with this
os.execute('export VAMP_PATH="'..script_path..'sonic/mac64/vamp"; cd "'..script_path..'sonic/mac64/"; ./sonic-annotator -d vamp:qm-vamp-plugins:qm-barbeattracker:beats -w csv "'..filename..'"')
To answer your actual question, you can start a Terminal and run some bash commands in it like this:
os.execute("osascript -e 'tell application \"Terminal\" to do script \"cd /Users/mark && ls\"'")
But, as I said in the comments, you don't necessarily need a Terminal to run a script, so you can just run a command like this:
os.execute("export V=fred; cd /Users/mark && ./SomeScript.sh")
If you are running a script because you just want the user to see the output of the script, it is often easier and involves far less quoting if you run your command and pipe the result to open -f like this, which displays the output in a text editor:
os.execute("cd /Users/mark; ls | open -f")

How can I skip errors and continue running Script?

I would like to know if it is possible to ignore a shell script command
and continue running the rest of the code, for example if the following
command return me nothing in the terminal and I continue to the next command.
EDIT:
I tried: 2>/dev/null
try
do shell script "kextstat|grep -y appleintel >/tmp/Intel.txt" with administrator privileges
on error
display alert "blabla..."
end try
end showIntel:```

Why isn't this command returning to shell after &?

In Ubuntu 14.04, I created the following bash script:
flock -nx "$1" xdg-open "$1" &
The idea is to lock the file specified in $1 (flock), then open it in my usual editor (xdg-open), and finally return to prompt, so I can open other files in sequence (&).
However, the & isn't working as expected. I need to press Enter to make the shell prompt appear again. In simpler constructs, such as
gedit test.txt &
it works as it should, returning the prompt immediately. I think it has to do with the existence of two commands in the first line. What am I doing wrong, please?
EDIT
The prompt is actually there, but it is somehow "hidden". If I issue the command
sudo ./edit error.php
it replies with
Warning: unknown mime-type for "error.php" -- using "application/octet-stream"
Error: no "view" mailcap rules found for type "application/octet-stream"
Opening "error.php" with Geany (application/x-php)
__
The errors above are not related to the question. But instead of __ I see nothing. I know the prompt is there because I can issue other commands, like ls, and they work. But the question remains: WHY the prompt is hidden? And how can I make it show normally?
Why isn't this command returning to shell after &?
It is.
You're running a command in the background. The shell prints a new prompt as soon as the command is launched, without waiting for it to finish.
According to your latest comment, the background command is printing some message to your screen. A simple example of the same thing:
$ echo hello &
$ hello
The cursor is left at the beginning of the line after the $ hello.
As far as the shell is concerned, it's printed a prompt and is waiting a new command. It doesn't know or care that a background process has messed up your display.
One solution is to redirect the command's output to somewhere other than your screen, either to a file or to /dev/null. If it's an error message, you'll probably have to redirect both stdout and `stderr.
flock -nx "$1" xdg-open "$1" >/dev/null 2>&1 &
(This assumes you don't care about the content of the message.)
Another option, pointed out in a comment by alvits, is to sleep for a second or so after executing the command, so the message appears followed by the next shell prompt. The sleep command is executed in the foreground, delaying the printing of the next prompt. A simple example:
$ echo hello & sleep 1
hello
[1] + Done echo hello
$
or for your example:
flock -nx "$1" xdg-open "$1" & sleep 1
This assumes that the error message is printed in the first second. That's probably a valid assumption for you example, but it might not be in general.
I don't think the command is doing what you think it does.
Have you tried to run it twice to see if the lock cannot be obtained the second time.
Well, if you do it, you will see that it doesn't fail because xdg-open is forking to exec the editor. Also if it fails you expect some indication.
You should use something like this
flock -nx "$1" -c "gedit '$1' &" || { echo "ERROR"; exit 1; }

Simply forking and redirecting the output of a command to /dev/null

I frequently execute from a shell (in my case Bash) commands that I want to fork immediately and whose output I want to ignore. So frequently in fact that I created a script (silent) to do it:
#!/bin/bash
$# &> /dev/null &
I can then run, e.g.
silent inkscape myfile.svg
and my terminal will not be polluted by the debug output of the process I just forked.
I have two questions:
Is there an "official" way of doing this?, i.e. something shorter but equivalent to &> /dev/null & ?
If not, is there a way I can make tab-completion work after my silent command as if it weren't there ? To give an example, after I've typed silent inksc, I'd like bash to auto-complete my command to silent inkscape when I press [tab].
aside: probably want to exec "$#" &> /dev/null & in your silent script, to cause it to discard the sub-shell, and the quotes around "$#" will keep spaces from getting in the way.
As for #2: complete -F _command silent should do something like what you want. (I call my version of that script launch and have complete -F launch in my .bash_profile)
It looks like nohup does more or less what you want. The tab-completion problem is because bash thinks that you are trying to complete a filename as an argument to the script, whereas its completion rules know that nohup takes a command as its first argument.
Nohup redirects stout and stderr to nohup.out and will also leave the command running if your shell exits.
Here's a little script I use for launching interactive (and chatty) X apps from e.g. an xterm
#!/bin/bash
exe="$1"
shift
"$exe" "$#" 2>/tmp/$$."$exe".err 1>&2 & disown $!
No output, won't die if the terminal exits, but in case something goes wrong there's a log of all output in /tmp
If you don't want the log just use /dev/null instead.
Also will work from a function if you're script-alergic.
Perhaps if you could 'rebind' the tab key? An example on superuser Stackoverflow with the enter key is shown. Is this the right idea?

Root user/sudo equivalent in Cygwin?

I'm trying to run a bash script in Cygwin.
I get Must run as root, i.e. sudo ./scriptname errors.
chmod 777 scriptname does nothing to help.
I've looked for ways to imitate sudo on Cygwin, to add a root user, since calling "su" renders the error su: user root does not exist, anything useful, and have found nothing.
Anyone have any suggestions?
I answered this question on SuperUser but only after the OP disregarded the unhelpful answer that was at the time the only answer to the question.
Here is the proper way to elevate permissions in Cygwin, copied from my own answer on SuperUser:
I found the answer on the Cygwin mailing list. To run command with elevated privileges in Cygwin, precede the command with cygstart --action=runas like this:
$ cygstart --action=runas command
This will open a Windows dialogue box asking for the Admin password and run the command if the proper password is entered.
This is easily scripted, so long as ~/bin is in your path. Create a file ~/bin/sudo with the following content:
#!/usr/bin/bash
cygstart --action=runas "$#"
Now make the file executable:
$ chmod +x ~/bin/sudo
Now you can run commands with real elevated privileges:
$ sudo elevatedCommand
You may need to add ~/bin to your path. You can run the following command on the Cygwin CLI, or add it to ~/.bashrc:
$ PATH=$HOME/bin:$PATH
Tested on 64-bit Windows 8.
You could also instead of above steps add an alias for this command to ~/.bashrc:
# alias to simulate sudo
alias sudo='cygstart --action=runas'
You probably need to run the cygwin shell as Administrator. You can right click the shortcut and click run as administrator or go into the properties of the shortcut and check it in the compatability section. Just beware.... root permissions can be dangerous.
Building on dotancohen's answer I'm using an alias:
alias sudo="cygstart --action=runas"
Works as a charm:
sudo chown User:Group <file>
And if you have SysInternals installed you can even start a command shell as the system user very easily
sudo psexec -i -s -d cmd
I found sudo-for-cygwin, maybe this would work, it is a client/server application that uses a python script to spawn a child process in windows (pty) and bridges user's tty and the process I/O.
It requires python in windows and Python modules greenlet, and eventlet in Cygwin.
It seems that cygstart/runas does not properly handle "$#" and thus commands that have arguments containing spaces (and perhaps other shell meta-characters -- I didn't check) will not work correctly.
I decided to just write a small sudo script that works by writing a temporary script that does the parameters correctly.
#! /bin/bash
# If already admin, just run the command in-line.
# This works on my Win10 machine; dunno about others.
if id -G | grep -q ' 544 '; then
"$#"
exit $?
fi
# cygstart/runas doesn't handle arguments with spaces correctly so create
# a script that will do so properly.
tmpfile=$(mktemp /tmp/sudo.XXXXXX)
echo "#! /bin/bash" >>$tmpfile
echo "export PATH=\"$PATH\"" >>$tmpfile
echo "$1 \\" >>$tmpfile
shift
for arg in "$#"; do
qarg=`echo "$arg" | sed -e "s/'/'\\\\\''/g"`
echo " '$qarg' \\" >>$tmpfile
done
echo >>$tmpfile
# cygstart opens a new window which vanishes as soon as the command is complete.
# Give the user a chance to see the output.
echo "echo -ne '\n$0: press <enter> to close window... '" >>$tmpfile
echo "read enter" >>$tmpfile
# Clean up after ourselves.
echo "rm -f $tmpfile" >>$tmpfile
# Do it as Administrator.
cygstart --action=runas /bin/bash $tmpfile
Or install syswin package, which includes a port of su for cygwin: http://sourceforge.net/p/manufacture/wiki/syswin-su/
This answer is based off of another answer. First of all, make sure your account is in the Administrators group.
Next, create a generic "runas-admin.bat" file with the following content:
#if (1==1) #if(1==0) #ELSE
#echo off&SETLOCAL ENABLEEXTENSIONS
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"||(
cscript //E:JScript //nologo "%~f0" %*
#goto :EOF
)
FOR %%A IN (%*) DO (
"%%A"
)
#goto :EOF
#end #ELSE
args = WScript.Arguments;
newargs = "";
for (var i = 0; i < args.length; i++) {
newargs += "\"" + args(i) + "\" ";
}
ShA=new ActiveXObject("Shell.Application");
ShA.ShellExecute("cmd.exe","/c \""+WScript.ScriptFullName+" "+newargs+"\"","","runas",5);
#end
Then execute the batch file like this:
./runas-admin.bat "<command1> [parm1, parm2, ...]" "<command2> [parm1, parm2, ...]"
For exaxmple:
./runas-admin.bat "net localgroup newgroup1 /add" "net localgroup newgroup2 /add"
Just make sure to enclose each separate command in double quotes. You will only get the UAC prompt once using this method and this procedure has been generalized so you could use any kind of command.
A new proposal to enhance SUDO for CygWin from GitHub in this thread, named TOUACExt:
Automatically opens sudoserver.py.
Automatically closes sudoserver.py after timeout (15 minutes default).
Request UAC elevation prompt Yes/No style for admin users.
Request Admin user/password for non-admin users.
Works remotely (SSH) with admin accounts.
Creates log.
Still in Pre-Beta, but seems to be working.
I landed here through google, and I actually believe I've found a way to gain a fully functioning root promt in cygwin.
Here are my steps.
First you need to rename the Windows Administrator account to "root"
Do this by opening start manu and typing "gpedit.msc"
Edit the entry under
Local Computer Policy > Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options > Accounts: Rename administrator account
Then you'll have to enable the account if it isn't yet enabled.
Local Computer Policy > Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options > Accounts: Administrator account status
Now log out and log into the root account.
Now set an environment variable for cygwin. To do that the easy way:
Right Click My Computer > Properties
Click (on the left sidebar) "Advanced system settings"
Near the bottom click the "Enviroment Variables" button
Under "System Variables" click the "New..." button
For the name put "cygwin" without the quotes.
For the value, enter in your cygwin root directory. ( Mine was C:\cygwin )
Press OK and close all of that to get back to the desktop.
Open a Cygwin terminal (cygwin.bat)
Edit the file /etc/passwd
and change the line
Administrator:unused:500:503:U-MACHINE\Administrator,S-1-5-21-12345678-1234567890-1234567890-500:/home/Administrator:/bin/bash
To this (your numbers, and machine name will be different, just make sure you change the highlighted numbers to 0!)
root:unused:0:0:U-MACHINE\root,S-1-5-21-12345678-1234567890-1234567890-0:/root:/bin/bash
Now that all that is finished, this next bit will make the "su" command work. (Not perfectly, but it will function enough to use. I don't think scripts will function correctly, but hey, you got this far, maybe you can find the way. And please share)
Run this command in cygwin to finalize the deal.
mv /bin/su.exe /bin/_su.exe_backup
cat > /bin/su.bat << "EOF"
#ECHO OFF
RUNAS /savecred /user:root %cygwin%\cygwin.bat
EOF
ln -s /bin/su.bat /bin/su
echo ''
echo 'All finished'
Log out of the root account and back into your normal windows user account.
After all of that, run the new "su.bat" manually by double clicking it in explorer. Enter in your password and go ahead and close the window.
Now try running the su command from cygwin and see if everything worked out alright.
Being unhappy with the available solution, I adopted nu774's script to add security and make it easier to setup and use. The project is available on Github
To use it, just download cygwin-sudo.py and run it via python3 cygwin-sudo.py **yourcommand**.
You can set up an alias for convenience:
alias sudo="python3 /path-to-cygwin-sudo/cygwin-sudo.py"
Use this to get an admin window with either bash or cmd running, from any directories context menue. Just right click on a directory name, and select the entry or hit the highlited button.
This is based on the chere tool and the unfortunately not working answer (for me) from link_boy. It works fine for me using Windows 8,
A side effect is the different color in the admin cmd window. To use this on bash, you can change the .bashrc file of the admin user.
I coudln't get the "background" version (right click into an open directory) to run. Feel free to add it.
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash]
#="&Bash Prompt Here"
"Icon"="C:\\cygwin\\Cygwin.ico"
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash\command]
#="C:\\cygwin\\bin\\bash -c \"/bin/xhere /bin/bash.exe '%L'\""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash_root]
#="&Root Bash Prompt Here"
"Icon"="C:\\cygwin\\Cygwin.ico"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash_root\command]
#="runas /savecred /user:administrator \"C:\\cygwin\\bin\\bash -c \\\"/bin/xhere /bin/bash.exe '%L'\\\"\""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_cmd]
#="&Command Prompt Here"
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_cmd\command]
#="cmd.exe /k cd %L"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_cmd_root]
#="Roo&t Command Prompt Here"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_cmd_root\command]
#="runas /savecred /user:administrator \"cmd.exe /t:1E /k cd %L\""
A very simple way to have a cygwin shell and corresponding subshells to operate with administrator privileges is to change the properties of the link which opens the initial shell.
The following is valid for Windows 7+ (perhaps for previous versions too, but I've not checked)
I usually start the cygwin shell from a cygwin-link in the start button (or desktop).
Then, I changed the properties of the cygwin-link in the tabs
/Compatibility/Privilege Level/
and checked the box,
"Run this program as an administrator"
This allows the cygwin shell to open with administrator privileges and the corresponding subshells too.
I met this discussion looking for some details on the sudo implementation in different operating systems. Reading it I found that the solution by #brian-white (https://stackoverflow.com/a/42956057/3627676) is useful but can be improved slightly. I avoided creating the temporary file and implemented to execute everything by the single script.
Also I investigated the next step of the improvement to output within the single window/console. Unfortunately, without any success. I tried to use named pipes to capture STDOUT/STDERR and print in the main window. But child process didn't write to named pipes. However writing to a regular file works well.
I dropped any attempts to find the root cause and left the current solution as is. Hope my post can be useful as well.
Improvements:
no temporary file
no parsing and reconstructing the command line options
wait the elevated command
use mintty or bash, if the first one not found
return the command exit code
#!/bin/bash
# Being Administrators, invoke the command directly
id -G | grep -qw 544 && {
"$#"
exit $?
}
# The CYG_SUDO variable is used to control the command invocation
[ -z "$CYG_SUDO" ] && {
mintty="$( which mintty 2>/dev/null )"
export CYG_SUDO="$$"
cygstart --wait --action=runas $mintty /bin/bash "$0" "$#"
exit $?
}
# Now we are able to:
# -- launch the command
# -- display the message
# -- return the exit code
"$#"
RETVAL=$?
echo "$0: Press to close window..."
read
exit $RETVAL
Based on #mat-khor's answer, I took the syswin su.exe, saved it as manufacture-syswin-su.exe, and wrote this wrapper script. It handles redirection of the command's stdout and stderr, so it can be used in a pipe, etc. Also, the script exits with the status of the given command.
Limitations:
The syswin-su options are currently hardcoded to use the current user. Prepending env USERNAME=... to the script invocation overrides it. If other options were needed, the script would have to distinguish between syswin-su and command arguments, e.g. splitting at the first --.
If the UAC prompt is cancelled or declined, the script hangs.
.
#!/bin/bash
set -e
# join command $# into a single string with quoting (required for syswin-su)
cmd=$( ( set -x; set -- "$#"; ) 2>&1 | perl -nle 'print $1 if /\bset -- (.*)/' )
tmpDir=$(mktemp -t -d -- "$(basename "$0")_$(date '+%Y%m%dT%H%M%S')_XXX")
mkfifo -- "$tmpDir/out"
mkfifo -- "$tmpDir/err"
cat >> "$tmpDir/script" <<-SCRIPT
#!/bin/env bash
$cmd > '$tmpDir/out' 2> '$tmpDir/err'
echo \$? > '$tmpDir/status'
SCRIPT
chmod 700 -- "$tmpDir/script"
manufacture-syswin-su -s bash -u "$USERNAME" -m -c "cygstart --showminimized bash -c '$tmpDir/script'" > /dev/null &
cat -- "$tmpDir/err" >&2 &
cat -- "$tmpDir/out"
wait $!
exit $(<"$tmpDir/status")
Can't fully test this myself, I don't have a suitable script to try it out on, and I'm no Linux expert, but you might be able to hack something close enough.
I've tried these steps out, and they 'seem' to work, but don't know if it will suffice for your needs.
To get round the lack of a 'root' user:
Create a user on the LOCAL windows machine called 'root', make it a member of the 'Administrators' group
Mark the bin/bash.exe as 'Run as administrator' for all users (obviously you will have to turn this on/off as and when you need it)
Hold down the left shift button in windows explorer while right clicking on the Cygwin.bat file
Select 'Run as a different user'
Enter .\root as the username and then your password.
This then runs you as a user called 'root' in cygwin, which coupled with the 'Run as administrator' on the bash.exe file might be enough.
However you still need a sudo.
I faked this (and someone else with more linux knowledge can probably fake it better) by creating a file called 'sudo' in /bin and using this command line to send the command to su instead:
su -c "$*"
The command line 'sudo vim' and others seem to work ok for me, so you might want to try it out.
Be interested to know if this works for your needs or not.
What I usually do is have a registry "Open Here" helper in order to open a cygwin shell with administrative privileges quite easy from anywhere in my computer.
Be aware you have to have the cygwin "chere" package installed, use "chere -i -m" from an elevated cygwin shell first.
Assuming your cygwin installation is in C:\cygwin...
Here's the registry code:
Windows Registry Editor Version 5.00
[-HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash]
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash]
#="Open Cygwin Here as Root"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Directory\shell\cygwin_bash\command]
#="c:\\cygwin\\bin\\mintty.exe -i /Cygwin-Terminal.ico -e /bin/xhere /bin/bash.exe"
[-HKEY_CLASSES_ROOT\Directory\Background\shell\cygwin_bash]
[HKEY_CLASSES_ROOT\Directory\Background\shell\cygwin_bash]
#="Open Cygwin Here as Root"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Directory\Background\shell\cygwin_bash\command]
#="c:\\cygwin\\bin\\mintty.exe -i /Cygwin-Terminal.ico -e /bin/xhere /bin/bash.exe"
[-HKEY_CLASSES_ROOT\Drive\shell\cygwin_bash]
[HKEY_CLASSES_ROOT\Drive\shell\cygwin_bash]
#="Open Cygwin Here as Root"
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\Drive\shell\cygwin_bash\command]
#="c:\\cygwin\\bin\\mintty.exe -i /Cygwin-Terminal.ico -e /bin/xhere /bin/bash.exe"
Hope this helps. Let me know if it works for you. Thanks.
PS: You can grab this code, copy and paste it and save it in a name.reg file to run it... or you can manually add the values.
Just simplifying the accepted answer, copy past the below in a Cygwin terminal and you are done:
cat <<EOF >> /bin/sudo
#!/usr/bin/bash
cygstart --action=runas "\$#"
EOF
chmod +x /bin/sudo
Try:
chmod -R ug+rwx <dir>
where <dir> is the directory on which you
want to change permissions.

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