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update readme

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Ben Harris 2016-10-30 20:21:39 -04:00
parent 5af4323348
commit 2d529ada0e
2 changed files with 82 additions and 67 deletions
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130
README.md
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@ -13,75 +13,75 @@ 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
+ 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).
+ `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).
Some cases to consider
+ A person tries to run a non-executable.
+ A person tries to read or write to a non-existant 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.
+ A person tries to run a non-executable.
+ A person tries to read or write to a non-existant 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.

19
bish.cc
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@ -1,14 +1,29 @@
#include <iostream>
#include <cstdlib>
#include <string>
#include <string.h>
#include <unistd.h>
using namespace std;
char** parse_line(char* line) {
char** cmd_w_args;
int cnt = 0;
char *pch = strtok (line," ");
while (pch != NULL) {
cmd_w_args[cnt] = pch;
pch = strtok (NULL, " "); cnt++;
}
return cmd_w_args;
}
int main(int argc, char **argv){
string line;
cout << getenv("PS1");
cout << "bish$ ";
while (getline(cin, line)) {
cout << line << endl;
cout << getenv("PS1");
execv(line, parse_line(line.c_str()), NULL);
cout << "bish$ ";
}
return 0;
}