benharri / bish Goto Github PK

If you use more than 3 lines of code from the internet, cite them in a comment. It's cause for an 'f' otherwise!!!!

THIS IS OUT OF 20 POINTS!!!! No one can get more than 20 points.

If you work in pairs, then I'll give each person 2/3 of the total points. So if a team gets 30 (and each person gets 15), I'll give each student 20.

If you work in threes, then I'll give each person 1/2 of the total points. So if a team gets 40 (and each person gets 13.3333), I'll give each student 20.

The Shell Assignment (total 42 points)

• 1 Can run an executable
  • /bin/ls
• 1 You search the path for the executable
  • ls
• 1 Can do file input redirection "<"
  • ls > fred
• 1 Can do file output redirection ">"
  • ls < fred
• 2 Can do command piping "|"
  • ls | wc
• 1 Can do lots of pipes
  • ls | grep fred | wc
• 1 Can do at least one combination of these things
  • ls | wc > fred
• 4 Can do any combination of three of <, >, and |
  • cat < filename | sort > sortedFile.txt
• 2 Can set enviornment variables
  • PATH=:/bin:/sbin:/usr/sbin:/usr/bin
• 2 Expands enviornment variables on the command line
  • ls $HOME
• 2 Does filename expansion "glob" (Hint: Use the built in glob.)
  • ls a*b
• 1 Knows how to change directory
  • cd /fred
• 1 Bang last command
  • !l runs ls
• 1 Bang # command
  • !4 runs 4th command from history
• 1 Queue commands
  • make ; make install
• 1 Can have lots of semicolons
  • ls; sleep 3; rm fred
• 2 Change Prompt
  • PS1="what is you command?"
• 3 Can run commands in the background.
  • processImage &
• 1 Concatenate commands with &. Only runs next command if the previous comand returned success.
  • cd /home/rappleto & rm fred.txt
• 1 Catch Keyboard interrupt
  • ctrl + c = back to prompt
• 1 Replace "~" with the home directory
  • rm ~/junkfile
• 1 Control-L clears the screen
  • ctrl-l = clear screen
• 3 When they misspell a command, offer a suggestion
  • (user) lss
  • (shell) Did you mean ls?
• 2 Can run commands from a file
  • . scriptFile.txt
• 2 Tab Completion and Arrow History
• 1 Saves and reloads history to a file
• 2 Automatically runs a file called .myshell when it starts
• 2 Only runs execuatables from an approved list
• -2 Commands cannot have arguments (i.e. ls -l does not work).

25 pts /20

Some cases to consider

• A person tries to run a non-executable.
• A person tries to read or write to a non-existent file.
• A person tries to read or write to a file they do not have permissions on.
• A person tries a non-sensical command. (i.e. ls > foo > fee < doo < dee)
• A person tries to pipe to a non-command (i.e. ls | /tmp/foo.txt)
• A person tries to pipe from a non-command (i.e. /tmp/foo | ls)
• A person tries to expand a non-variable (i.e. ls $DOES_NOT_EXIST)
• A regular expression matches no files.
• A regular expression matches one file.
• A regular expression matches lots of files.
• A person tries to change directory to something that does not exist.

These programs are due Friday before finals week. It will take a totally excellent excuse to move this at all.