/rshell

cs 100 shell

Primary LanguageC++OtherNOASSERTION

rshell

cs 100 shell

Building and Running

make
./bin/rshell

Features

  • Supports up to 1000 chained commands in a single entry
  • Includes login and hostname in prompt
kkita004@hammer.cs.ucr.edu$
  • Automatically trims tabs (at beginning and end of input) and excess spaces (at all parts) from commands
kkita004@hammer.cs.ucr.edu$               ls                                   -a             -a;

becomes

kkita004@hammer.cs.ucr.edu$ ls -a -a;
  • Supports both single and double quotes
kkita004@hammer.cs.ucr.edu$ echo "This sentence will be output."
This sentence will be output.
kkita004@hammer.cs.ucr.edu$ echo "The ; && and || will be ignored while in these quotes."
The ; && and || will be ignored while in these quotes.

An error will be detected if quotes are left unclosed.

  • Empty input is ignored

  • If an empty command is entered, it will stop the remaining chain of commands from working

kkita004@hammer.cs.ucr.edu$ echo testing &&     ; echo "will not appear"
testing

  • Now supports piping and redirection with < > and |

  • Can also append by using >>

  • Can chain any number of pipes and redirection at the same time

  • Can now change directories using the cd command

  • Using cd by itself will go to home directory

  • Using cd - will go to previous directory

  • If cd - is used before any other cd, then it will lead to home directory

Dependencies

Uses the boost library for trimming and tokenizing. Uses C++11 features.

Known Bugs and Limitations

  • Inline tabs will not be ignored in commands
kkita004@hammer.cs.ucr.edu$ ls -a \t\t\t -a
: invalid option -- ' '
Try 'ls --help' for more information.

  • Cannot handle hostnames or login names that are longer than 256 characters.

  • Does not currently handle input/output redirection or piping

  • Does not support single quotes within quotes

echo 'You're it!';
error: no closing single quotation found

  • Attempting to use cd - without prior changing directories will send you to $HOME.

  • Cannot pipe the cd command. Doing so will result in cd executing and nothing else in the chain of pipes.

  • Redirecting input to/from cd will result in only the command cd executing, as the redirections are removed

ls

cs 100 ls

Building and Running

make
bin/ls

Features

  • Accepts multiple directory inputs
bin/ls dir1, dir2 dir3
  • Adjusts formatting to accomodate file sizes
  • Accepts 3 flags, -a, -l, and -R in any combination
$ bin/ls -laR
$ bin/ls -Ral
$ bin/ls -R -a -l

Will all result in the same output

  • Outputs almost exactly like standard ls

Dependencies

Uses the boost library for trimming and tokenizing. Uses C++11 features. Requries a Unix machine.

Known Bugs and Limitations

  • Does not accept files as input, only directories
$ touch foo
$ bin/ls foo
  • Cannot bring back the dead
  • Redirection must have the program name come first
$ < in cat > out
Will result in error
  • Redirection does not support output redirection before a pipe
$ cat < in > out | wc
Will result in error
  • Redirection does not support file descriptors (e.g. 2>)
  • Redirection does support string redirection (e.g. <<<)