Midterm Questions Flashcards
What would you type at the command line if you wanted to see the value of the variable SHELL?
echo $SHELL
What would you type at the command line if you wanted to see the last 10 lines of the file log.txt?
tail log.txt
What is the name of the directory at the top of the Unix filesystem?
root
What symbol is used to represent the top of the Unix filesystem?
/
What is the parent directory?
the directory directly above your current directory
Can you have two files with the same name in the same directory?
no
What directory are you in when you first log in to a Unix machine?
your own home directory
What does the .. (dot dot) in your current directory mean?
the parent directory of your current directory
What directory is the starting point for an absolute path?
the root directory
What directory is the starting point for a relative path?
the current directory
By default, which account is the owner of a file or directory?
the account that created it
Name the three types of access permissions.
read, write and execute
Name the three categories of accounts which are used in assigning access permissions.
owner, group, everyone else
What does the PATH shell variable contain?
the list of directories the shell must search to find the file to run a command
If you wanted the program do_something to take input from the file data.txt what would you write at the command line?
do_something < data.txt
Look at the diagram on the last page. Assuming that you are in the directory named it, write the absolute pathname you would use to reference the directory named hw inside the it117 directory. You do not have to write a Unix command, I only want the pathname.
/courses/it/it117/hw
Look at the diagram on the last page. Assuming that you are in the directory named it, write the relative pathname you would use to reference the directory named hw1 under the it244 directory. You do not have to write a Unix command, I only want the pathname.
it244/hw/hw1
Look at the diagram on the last page. Assuming that you are in the directory named it, write the relative pathname you would use to reference the root directory. You do not have to write a Unix command, I only want the pathname.
../..
Look at the diagram on the last page. z Assuming that you are in the directory named it, write the relative pathname you would use to reference the bill directory. You do not have to write a Unix command, I only want the pathname.
../../home/bill
Look at the diagram on the last page. Assuming that you are in the directory bill, write the command to create a soft link to the hw2 directory. You may use either an absolute or relative pathname.
ln -s /courses/it/hw/hw2
Write the single command you would use to change the permissions on the file memo.txt so that the owner could read and write it, the group could only read it and all other users had no permissions whatsoever.
chmod 640 memo.txt
Write the single command you would use to change the permissions on the file backup so the owner had all permissions, the group could read and execute the file and all other users cold only execute the file.
chmod 751 backup
Write the single command you would use to change the permissions on the directory work so that the owner could do anything, the group could run ls and cd on the directory and all other users could only run ls on the directory.
chmod 754 work
Write a single command to create a copy of the file memo.txt in the parent directory into the current directory.
cp ../memo.txt .
Using a pipe, write the command line to find all Red Sox games from the file redsox.txt where the Sox lost to a team that was not the Orioles. Entries in the file look like this
2011-07-02 Red Sox @ Astros Win 7-5
2011-07-03 Red Sox @ Astros Win 2-1
2011-07-04 Red Sox vs Blue Jays Loss 7-9
2011-07-05 Red Sox vs Blue Jays Win 3-2
…
grep Loss redsox.txt | grep -v Orioles
