Variable assignment fails if called with sudo - shell

I have to do an assignment like m=7 from the C++ command line application. When I run this application using sudo MyApp, the command present in the program fails to execute.
sudo m=7
fails with the following error
Command Not Found.
Is there any way so that I can assign value to a variable with the sudo keyword present in the command?
Basically I want a way to do sudo {Assignment} i.e. sudo m=3. Thanks.

The sudo command allows one to run an external command as a given user (default: root). m=7 is not an external command and hence cannot be run by sudo. It is a variable assignment statement that is directly interpreted and executed by the current shell.
The Command not found message indicates that sudo failed to find an executable command named m=7.
In fact, it is hard to imagine what the intended goal of running sudo m=7 might be. If you want to assign 7 to the shell variable m you do not need any special privileges or sudo for that, just run m=7. If you want to open root shell and execute some commands there starting with m=7 just start with sudo bash and then issue the m=7 statement.

Related

sudo: command not found while using plink

Hi i have created a batch file (run.bat) that after execution connects me to UNIX server with help of plink. But issue starts from this point i have to execute a script after connection to my server the script contains a command sudo -l. After the execution i get the error as mentioned in subject can anyone help me on this issue ??
Batch File-:
"C:\Program Files\PuTTY" plink -ssh -pw Tos#12Ts w44dvftyw#caa1607UX009.wvd.abcd.net /opt/sieb/w44dvftyw/run.sh
Script file(run.sh) -:
#!/bin/bash
sudo -l
It says
sudo: command not found
But when i run my script normally on UNIX server it runs with no issues. What am i missing here to make it work this way please help.
Scripts such as ~/.profile or ~/.bash_profile responsible for setting up the current user's PATH are run only on login shells.
Running sh -c 'somescript' (as performed by ssh host 'somescript') is neither a login shell, nor an interactive shell; thus, it does not gain the benefit of such scripts.
This means that additions to the PATH (in your case, /usr/local/bin) may not be present with commands run in this way.
Among your options:
Pass the PATH you want as part of the command to remotely run. This might look like:
plink -ssh user#host "PATH=/bin:/usr/bin:/usr/local/bin /opt/sieb/w44dvftyw/run.sh"
Embed a working value in the script you're running:
#!/bin/bash
PATH=/bin:/usr/bin:/usr/local/bin
# ...put the rest of your script here.

Bash script - change to root then exit root

If I am in the middle running a bash script, is there any way to switch over to root user, process a command, and then exit root mode? For example, I'd like to include these commands in the middle of a bash script:
sudo su
umount /home/user/myMount
exit
The problem is that after the first line runs, the shell goes into root mode, but then stops execution. Of course, I could create and execute a second script at this point, but this defeats the purpose of scripting since I could just type the commands myself.
The other obvious idea is to run the script from with the root user at the outset. However, some of the other commands in this script fail if I am the root user since they would expose security vulnerabilities with this much access.
So, I need a way to get into the root and then exit out of it.
Thanks.
Specify a Command
The sudo command can take a command and optional arguments. For example:
sudo umount /home/user/myMount
This will run only the specified command and its arguments as root. If you want to run the command as another user, you can use the -u flag. For example, to run umount as Fred, you could use:
sudo -u fred umount /home/user/myMount
While there are certainly other ways to address this issue, this is by far the simplest and most common.
In order to perform the umount as root, use
sudo umount /home/user/myMount

Execute single command in shell script without sudo

I have a simple shell script that is run with sudo as most of the script requires it, yet one of the commands in the script is a Homebrew install, which cannot be executed with sudo..
So, my question is when executing a shell script with sudo how do I execute sub commands as the current user and then continue the remainder of the script with sudo.
Prompting the user to enter his password again is not really practical as the script takes really long to execute and would require waiting 5-10 min for the prompt.
The easiest way is to run the subcommand via sudo from within the script. The user id to run with can be obtained by $SUDO_USER (look at the output of sudo env):
sudo -u $SUDO_USER ./exec_as_normal_user.sh
Instantiate the shell using
sudo -u $USER_NAME bash
and execute the shell script by calling,
./program.sh

How to use sudo inside of a Run Script build phase in Xcode 4?

I need use execute a command inside of a script in a Run Script build phase in Xcode 4 using sudo. However, the compiler complains:
sudo: no tty present and no askpass program specified
Anyone have a clever solution for this problem?
One solution is to place the sudo password in an executable shell script like the following:
#!/bin/bash
echo thesudopassword
This shell script might be called password.sh
Then, setup the environment variable SUDO_ASKPASS=password.sh
Once this is setup, the -A option can be passed to sudo. This option uses the ASKPASS program to obtain the sudo password. The ASKPASS program need only write the password to stdout.
So, for example,
sudo -A ditto -V /tmp/testserver.dst /
This is obviously a rather insecure solution, but it does work.
Two ideas that haven't been suggested yet, both of which are probably better/safer than the currently accepted answer:
First option would be to put the part of the script that needs to be run as root in a script file (.sh or something), and then make it setuid as root: chmod go-w,+sx scriptfile, sudo chown root scriptfile. This means that script will automatically run as root, which avoids you needing to authenticate to run it (just to change it). As long as its operation isn't subject to user input, this should be quite safe. (Of course, if you make a script that takes an input argument and deletes it or runs it, or does most anything else with it, that would not be safe.)
Second option would be to use applescript (possibly via osascript). Applescript allows you to do shell script "sudo command goes here" with administrator privileges, which will pop up a graphical dialog asking for a password.
The first of these options would be good for an automated environment, though it might not deal well with (for example) being checked into an SCM, or being sent to another user. The second option would work better with that, but requires a password input every time, so doesn't work as well for an automated build script.
Another solution to this problem is to modify sudoers file and add your account to it and state that you should never be asked for the sudo password. To accomplish this is fairly straightforward:
run:
sudo visudo
In the User privilege specification section add a line that looks like
youraccountname ALL=(ALL) NOPASSWD: ALL
Of course, this can be a dangerous thing to do, so be careful. I would suggest reading the man page for sudoers and visudo before going this route.
After much searching I found the following solution.
https://forum.juce.com/t/build-script-for-automatically-moving-built-aus-into-components-folder-xcode/13112
Summary
Create a keychain and store your admin password in the keychain
Create a script which uses /usr/bin/security to access the password In your run script,
Set the ASK_PASS env variable and use the -A option with sudo
You can either run commands directly as a administrator with the following (changing echo YourCommandHere > /tmp/hello to your command):
osascript -e 'do shell script "sudo echo YourCommandHere > /tmp/hello " with administrator privileges'
Or run a script in your source directory using:
osascript -e 'do shell script "bash -x $SOURCE_ROOT/MyAdminScript.sh 1>/tmp/build-log 2>/tmp/build-log.err" with administrator privileges'
This runs the script and logs it output to /tmp/build-log and /tmp/build-log.err
For useful variables in the script see https://help.apple.com/xcode/mac/8.0/#/itcaec37c2a6
You can also execute XCode giving it the project as parameter from the Terminal using sudo like this:
sudo /Developer/Applications/Xcode.app/Contents/MacOS/Xcode /path/to/your/project.xcodeproj
This is the easiest solution I could think of, but there may be some drawbacks, since you would be executing XCode as root.
No need to write your sudo password anywhere. Just open a terminal window and type
$ sudo echo "hello"
Once you've typed your password, it will be good for a while - not sure how long - and the shell spawned by Xcode will inherit this permission.
If you get the "no tty present" message again later, just repeat the procedure

Capistrano :shell example

I'm currently using Capistrano to deploy my web application which works like a charm.
In my new project I must execute a command from sudo /bin/bash shell.
Is it possible for Capistrano to login to the machine as user X, run sudo /bin/bash,
enter the password and then execute a command in the sudo shell? If yes, could you
please provived me with an example.
With regards
jakob
Is there a specific reason you need to be in a root shell rather than executing the command with sudo? If executing a command with sudo, you can simply sudo 'command' instead of run 'command'.
I did a little experimentation to try to get a root shell with capistrano without logging into the server directly as root, and wasn't able to make much progress.
If running with sudo won't work, please update your question to let us know why and maybe we can help you find a workaround for it.
Update:
After playing around a little more, I found that you can execute an individual command (or string of commands) in a root shell by doing something like sudo '/bin/bash -c "whoami"'. It's getting an interactive root shell that's tricky.

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