This quiz is part of the DevOpsTheHardWay course.

Bash - loops - multichoice questions

Given the following script, answer the following 3 questions:

[elvis@station elvis]$ cat script
#!/bin/bash

for i in $*
do
  if [ -r $i ]
  then
    gzip $i
  else
    echo "cannot compress $i"
  done
fi

[elvis@station elvis]$ ./script rotate_cw
./script: line 10: syntax error near unexpected token `done'
./script: line 10: `
done'

Question 1

Which of the following lines could replace the line if [ -r $i ] above, with no effect on script execution?

• if test -r $i
• if [-r $i]
• if [ -r -o $i ]
• if [ -e $i
• None of the above

Question 2

What syntax error exists in the script?

• The words for and do must occur on the same line.
• There must be no spaces between [ and -r on the line starting if.
• The gzip command must be specified using an absolute reference.
• The last line contains the misspelled word fi.
• The last two lines (containing done and fi) need to be transposed.

Question 3

What does the variable i iterate through (assuming the syntax error mentioned above is fixed)?

• All (non-hidden) files in the local directory.
• All files in the local directory.
• All files which were previously defined in the environment variable named *.
• All of the command line arguments provided when the script was invoked.
• None of the above.

Question 4

The following text is found in the file /etc/bashrc.

if [ "$(id -gn)" = "$(id -un)" -a "$(id -u)" -gt "99" ]; then
  umask 002
else
  umask 022
fi

Which of the following best describes the execution of this text?

• If the current user is a member of more than one group, then set the current shell's umask to 002, otherwise set it to 022.
• If the current user's group name is the same as the user's username, or the user has a userid greater than 99, set the shell's umask to 002, otherwise set it to 022.
• If the user is a member of more than 99 groups, set the shell's umask to 002, otherwise set it to 022.
• If the current user is the root user, set current shell's umask to 002, otherwise set it to 022.
• If the current user's group name is the same as the user's username, and the user has a userid greater than 99, set the shell's umask to 002, otherwise set it to 022.

Question 5

The following text is found in the file /etc/profile.

for i in /etc/profile.d/*.sh ; do
  if [ -r "$i" ]; then
    . $i
  fi
done

Which of the following best describes the execution of this text?

• For every file in the /etc/profile.d directory that ends .sh, if it is readable, source it.
• For every file in the /etc/profile.d directory that ends .sh, if it is executable, source it.
• For every file in the /etc/profile.d directory that ends .sh, if it is not a directory, source it.
• None of the above.

Question 6

The following text is found in the file /etc/profile.

for i in /etc/profile.d/*.sh ; do
  if [ -r "$i" ]; then
    . $i
  fi
done

What innocent action could a system administrator make that causes an error (exit status other than 0) when this section of the above script is executed?

• The administrator could place a file that does not end with .sh in the /etc/profile.d directory.
• The administrator could place a file that does not have executable permissions in the /etc/profile.d directory.
• The administrator could place a file that does not have read permissions in the /etc/profile.d directory.
• The administrator could place a file that does not have write permissions in the /etc/profile.d directory.
• The administrator could place a file titled source me.sh in the /etc/profile.d directory.
• None of the above