I have been trying to make a shell script in bash that will display the following:
You are the super user (When I run the script as root). You are the user: "user" (When I run the script as a user).
#!/bin/bash/
if { whoami | grep "root" }; then
echo $USER1
else
echo $USER2
fi
I keep recieving these syntax error messages:
script.sh: line 2: syntax error near unexpected token `then'
script.sh: line 2: `if { whoami | grep "root" }; then'
Could someone help me out?
If braces are used to chain commands then the last command must have a command separator after it.
{ foo ; bar ; }
if whoami | grep root; then....ignoring the more obvious solution using id instead of whoami userType="$(whoami)"
if [ "$userType" = "root" ]; then
echo "$USER1"
else
echo "$USER2"
fi
grep...
pay attention with your first line, the correct syntax for she-bang is:
#!/bin/bash
everything you put there, is the interpreter of your script, you can also put something like #!/usr/bin/python for python scripts, but your question is about the if statement, so you can do this in two ways in shell script using
if [ test ] ; then doSomething(); fi
or
if (( test )) ; then doSomething(); fi
so to answer your question basically you need to do this
#!/bin/bash
if [ `id -u` -eq 0 ] ; then
echo "you are root sir";
else
echo "you are a normal user"
fi
if (( "$USER" = "root" )); then
echo "you are root sir";
else
echo "you are a normal user"
fi
note that you could use a command using `cmd` or $(cmd) and compare using -eq (equal) or = (same), hope this help you :-)
if tests the success or failure of a command. [ ... ] is just a special case of that (yes, [ is actually a command, not part of the shell's syntax, though it's typically a built-in command). Since the OP specifically wants to test the success or failure of the whoami | grep "root" command, there's no need for [ ... ] or (( ... )).if [ $(id -u) -eq 0 ] ; then is probably the cleanest solution. Note that testing $USER can be unreliable, since any user can change the value of the $USER environment variable.
;before the}. As the comment on that answer says, you don't need{...}at all. And once you get that fixed, you'll probably want to usegrep -qto hide the output, since all you care about is success or failure. Also, a simplegreplike this will give you a false positive if your user name is, for example,notroot.[ $(id -u) = 0]is probably the most reliable method. Grepping for the stringrootcan give you false positives, and$USERcan be changed by the user.