MacOS – Behavior of login shell vs. Linux, ‘sh -c’

bashcommand linemacos

I have a seemingly-valid command that works fine on Linux boxes but fails on OSX, and I would like to know why.

sudo su - validusername sh -c 'whoami'

On Linux, this will echo 'validusername' on the console. OSX however, shows an error:

/bin/sh: /bin/sh: cannot execute binary file

Is this an OSX particularity? Or is it due to the fact that OSX uses bash 3.2, while our linux boxes are on bash 4.x?

EDIT: I figured out a workaround quickly (sudo -u), I am mainly interested in learning why this happened. Thanks!

Best Answer

try

sudo -su validusername sh -c 'whoami'

Related Solutions

Porting Linux shell scripts

Short answer: whichever suits you.

If your Unix background is mainly from Linux, you’re probably used to GNU commands. As you’ve noticed, they can be different from other Unix/Unix-based operating systems. Depending on how complex your scripts are, you can either:

make simple changes (like using ls -R . instead of ls . -R), which will work in most (if not all) Unix/Unix-based system and not only on GNU-based ones,
or install the GNU utilities from MacPorts if you think that there’d be too many/complex changes, or if you prefer to stick to the GNU commands you’re already used to.

If you want to take some time and write portable scripts, do it. If you think that’s not worth it, then don’t. Just bear in mind that not every Unix/Unix-based system uses GNU by default.

Shell script help

This should work. I don't have time currently to explain the changes/additions, but I'll update. You must run this script as sudo for it to work.

Even easier, sudo chmod +s yourscript - will run as root without requiring password.

#!/bin/bash

#Machines must have cURL installed as a prerequisite to download software from internet or FTP server 

#Change to your working directory. 
cd ~/Downloads

#grab files from www.teamviewer.com or custom FTP server
curl -O http://downloadus3.teamviewer.com/download/TeamViewerHost.dmg

#grab TeamViewer from custom FTP server
curl -O https://www.dropbox.com/s/******/com.apple.TeamViewer8.Settings.plist

#Place customized plist file into Library/Preferences
mv ~/Downloads/com.apple.TeamViewer8.Settings.plist /Library/Preferences/

#Mount and Install TeamViewer
hdiutil mount ~/Downloads/TeamViewerHost.dmg
installer -pkg /Volumes/TeamViewerHost/Install\ TeamViewerHost.pkg -target LocalSystem

#Softkill process in order to unmount package
ps aux | grep -i TeamViewer | awk {'print $2'} | xargs kill

#Unmount package
hdiutil unmount /Volumes/TeamViewerHost/

Best Answer

Related Solutions

Porting Linux shell scripts

Shell script help

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