I am trying to create a shell script where it uses the root access to install all the dependencies and after completing it, it exits from the root command and continue executing the script as normal user.
This is the test code:
#!/bin/sh
output=$(whoami)
if [ "$(whoami)" != "root" ]
then
su -c "echo \"hi\""
echo $output
//continue doing some installtion
exit
fi
echo $output //this should show the normal username not the root name
#!/bin/sh
su -c 'echo $(whoami)'
echo $(whoami)
When you pass the command with su following with an option -c it runs as root user, so when you want to install any dependencies you can run the following command as shown in above example.
Related
Can I change/su user in the middle of a script?
if [ "$user" == "" ]; then
echo "Enter the table name";
read user
fi
gunzip *
chown postgres *
su postgres
dropdb $user
psql -c "create database $user with encoding 'unicode';" -U dbname template1
psql -d $user -f *.sql
You can, but bash won't run the subsequent commands as postgres. Instead, do:
su postgres -c 'dropdb $user'
The -c flag runs a command as the user (see man su).
You can use a here document to embed multiple su commands in your script:
if [ "$user" == "" ]; then
echo "Enter the table name";
read user
fi
gunzip *
chown postgres *
su postgres <<EOSU
dropdb $user
psql -c "create database $user with encoding 'unicode';" -U dbname template1
psql -d $user -f *.sql
EOSU
Not like this. su will invoke a process, which defaults to a shell. On the command line, this shell will be interactive, so you can enter commands. In the context of a script, the shell will end right away (because it has nothing to do).
With
su user -c command
command will be executed as user - if the su succeeds, which is generally only the case with password-less users or when running the script as root.
Use sudo for a better and more fine-grained approach.
Refer to answers in below question,
You can write between << EOF and EOF as mentioned in answers.
#!/bin/bash
whoami
sudo -u someuser bash << EOF
echo "In"
whoami
EOF
echo "Out"
whoami
How do I use su to execute the rest of the bash script as that user?
No you can't. Or atleast... you can su but su will simply open a new shell at that point and when it's done it will continue with the rest of the script.
One way around it is to use su -c 'some command'
Another interesting idea that I heard today is to do a recursive call on the script, when you run as root and you want to run the script as another user. See the example below:
I am running script "my_script" as "root" and want the script to run as user "raamee"
#!/bin/bash
#Script name is: my_script
user=`whoami`
if [ "$user" == "root" ]; then
# As suggested by glenn jackman. Since I don't have anything to run once
# switching the user, I can modify the next line to:
# exec sudo -u raamee my_script and reuse the same process
sudo -u raamee my_script
fi
if [ "$user" == "raamee" ]; then
#put here the commands you want to perform
do_command_1
do_command_2
do_command_3
fi
I have below script named as sample.sh
#!/bin/bash
echo "inside script file"
echo whoami
echo cftping -v
echo "Ping completed"
I am running it as other user with the help of below command.
sudo -H -u xfbcft bash -c 'bash /data/_temp/sample.sh'
I am getting below output:
xfbcft
/data/_temp/sample.sh: line 4: cftping: command not found
Ping completed
When I sudo to xfbcft directly then I can run 'cftping -v' command but not via above shell script. Could anyone guide me here?
How do I write a shell script that continues execution even if a specific command failed, however I want to output as error later, I tried this:
#!/bin/bash
./node_modules/.bin/wdio wdio.conf.js --spec ./test/specs/login.test.js
rc=$?
echo "print here"
chown -R gitlab-runner /gpc_testes/
chown -R gitlab-runner /gpc_fontes/
exit $rc
However the script stops when the node modules command fails.
You could use
command_that_would_fail || command_failed=1
# More code and even more
.
.
if [ ${command_failed:-0} -eq 1 ]
then
echo "command_that_would_fail failed"
fi
Suppose name of the script is test.sh.
While executing the scripting, execute it with below command
./test.sh 2>>error.log
Error due bad commands won't appear on terminal but will be stored in file error.log which can be referred afterwards.
I have a shell script as given below.
#!/bin/bash
sudo -u testuser -H sh -c "
mkdir /usr/local/testdir;
if [ $? -eq 0 ];then
echo "Successfull";
else
echo "Unsuccessfull";
fi
"
I have given privileges to user testuser to execute shell script with sudo, but without asking password.For this I add the below line in /etc/sudoers file,
testuser ALL=(ALL) NOPASSWD: ALL
And it works fine that, I could run commands with sudo, but without asking password. But the above shell script always giving out put ass follows,
mkdir: cannot create directory `/usr/local/testdir': Permission denied
Successfull
And it is not creating directory testdir inside /usr/local. Please advice me what modification shall I need to do to work this script fine.
Thanks.
Two problems:
1.) You told:
sudo -u testuser -H ...
what's mean: run the command as testuser, and he doesn't has permissions to write into the /usr/local therefore you getting permission denied.
When you remove the -u testuser, the command will run as root (as default) (without password for the testuser) and will create the directory.
Seems, you simply misunderstand how the sudo and /etc/sudoers works. The -u user mean
-u user' The -u (user) option causes sudo to run the specified command as a user
other than root. To specify a uid instead of a user name, #uid.
When running commands as a uid, many shells require that the '#' be escaped with a
backslash ('\'). Security policies may restrict uids
to those listed in the password database. The sudoers policy allows
uids that are not in the password database as long as the targetpw
option is not set. Other security policies may not support this.
2.) second problem the Successfull message.
You're using double quotes for sh -c. The Variable expansion is done BEFORE the sh -c even starts. So use single quotes, and will get the correct Unsuccessfull message:
sudo -u testuser -H sh -c '
mkdir /usr/local/testdir
if [ $? -eq 0 ];then
echo "Successfull";
else
echo "Unsuccessfull";
fi
'
and use the next as a solution:
sudo -H sh -c '
mkdir /usr/local/testdir
if [ $? -eq 0 ];then
echo "Successfull";
else
echo "Unsuccessfull";
fi
'
Can I change/su user in the middle of a script?
if [ "$user" == "" ]; then
echo "Enter the table name";
read user
fi
gunzip *
chown postgres *
su postgres
dropdb $user
psql -c "create database $user with encoding 'unicode';" -U dbname template1
psql -d $user -f *.sql
You can, but bash won't run the subsequent commands as postgres. Instead, do:
su postgres -c 'dropdb $user'
The -c flag runs a command as the user (see man su).
You can use a here document to embed multiple su commands in your script:
if [ "$user" == "" ]; then
echo "Enter the table name";
read user
fi
gunzip *
chown postgres *
su postgres <<EOSU
dropdb $user
psql -c "create database $user with encoding 'unicode';" -U dbname template1
psql -d $user -f *.sql
EOSU
Not like this. su will invoke a process, which defaults to a shell. On the command line, this shell will be interactive, so you can enter commands. In the context of a script, the shell will end right away (because it has nothing to do).
With
su user -c command
command will be executed as user - if the su succeeds, which is generally only the case with password-less users or when running the script as root.
Use sudo for a better and more fine-grained approach.
Refer to answers in below question,
You can write between << EOF and EOF as mentioned in answers.
#!/bin/bash
whoami
sudo -u someuser bash << EOF
echo "In"
whoami
EOF
echo "Out"
whoami
How do I use su to execute the rest of the bash script as that user?
No you can't. Or atleast... you can su but su will simply open a new shell at that point and when it's done it will continue with the rest of the script.
One way around it is to use su -c 'some command'
Another interesting idea that I heard today is to do a recursive call on the script, when you run as root and you want to run the script as another user. See the example below:
I am running script "my_script" as "root" and want the script to run as user "raamee"
#!/bin/bash
#Script name is: my_script
user=`whoami`
if [ "$user" == "root" ]; then
# As suggested by glenn jackman. Since I don't have anything to run once
# switching the user, I can modify the next line to:
# exec sudo -u raamee my_script and reuse the same process
sudo -u raamee my_script
fi
if [ "$user" == "raamee" ]; then
#put here the commands you want to perform
do_command_1
do_command_2
do_command_3
fi