253 lines
8.6 KiB
Markdown
253 lines
8.6 KiB
Markdown
# Minishell
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A lot of amazing shell stuff
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## Dependencies
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- libreadline-dev
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- libncurses-dev
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##EVALS
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- [ ] exit code niet perse de laatste command race condition?
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- [ ] heredoc quote + variable expansion
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## Comments on work
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- Checked if path is a directory and send appropriate message
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- `executor_absolute_path` => extracted some code into helpers to make it norminette compliant
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- `executor_child` => refactored putstr_fd into error_msg | checked if file on path is exectuable to show permission denied where applicable
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- `lexer_token_next` => extracted code for norminette
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- `parser` => **A LOT** of work in all files for norminette compliancy
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- `expander_parse_string` => Fixed so that $HOME/test.txt returns the correct path and file
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## Edge Cases
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- `cat $PWD/test` should expand,
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- `cd -` : `bash: cd: OLDPWD not set`
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- `cd ~` : does not expand ?
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- ~ does expand in bash but not in any quotes
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- `echo a '' b` = "a b" ipv "a b"
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## Tester
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- [minishell_tester](https://github.com/LucasKuhn/minishell_tester)
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- [python tester](https://minishell-test.readthedocs.io/en/latest/index.html)
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## TODO
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- CTRL+C on input line results in exit code 130 in bash. -> this is signal global
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- `cat | cat | ls` isn't blocking. (processes appear to be active while parent moves on)
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- `echo $USER" $PWD` -> match quotes and throw error.
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- CB command to change banner
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- __Bonus:__ Command tree for &&, ||, *
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## Signals
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### In interactive mode
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- `ctrl - C` redisplay prompt status 130
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- `ctrl - D` exit shell
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- `ctrl - \`
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-- Done
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### During process
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- `ctrl - C` SIGINT to processs status 130
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- `ctrl - D`
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- `ctrl - \` SIGQUIT to process core dumped status 131
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-- Shows ^C
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### During HEREDOC
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- `ctrl - C` redisplay prompt status 130
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- `ctrl - D` SEND EOF error displayed but still works status:0
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- `ctrl - \` nothing
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## Allowed Functions
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### `<readline/readline.h>`
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* `readline`
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* `char *readline(const char *prompt);`
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* Reads a line from the terminal with editing capabilities.
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* `rl_clear_history`
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* `void rl_clear_history(void);`
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* Clears the history of lines read by readline.
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* `rl_on_new_line`
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* `int rl_on_new_line(void);`
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* Resets the state to indicate that a new line of input is being read.
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* `rl_replace_line`
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* `int rl_replace_line(const char *text, int clear_undo);`
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* Replaces the contents of the current line with text.
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* `rl_redisplay`
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* `int rl_redisplay(void);`
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* Redisplays the current input line.
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* `add_history`
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* `void add_history(const char *line);`
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* Adds the line to the history list.
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### `<stdio.h>`
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* `printf`
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* `int printf(const char *format, ...);`
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* Sends formatted output to stdout.
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### `<stdlib.h>`
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* `malloc`
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* `void *malloc(size_t size);`
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* Allocates size bytes of memory and returns a pointer to the allocated memory.
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* `free`
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* `void free(void *ptr);`
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* Frees the memory space pointed to by ptr, which must have been returned by a previous call to malloc.
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### `<unistd.h>`
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* `write`
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* `ssize_t write(int fd, const void *buf, size_t count);`
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* Writes up to count bytes from the buffer starting at buf to the file referred to by the file descriptor fd.
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* `access`
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* `int access(const char *pathname, int mode);`
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* Checks the file named by pathname for accessibility according to the bit pattern contained in mode.
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* `open`
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* `int open(const char *pathname, int flags, ...);`
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* Opens a file specified by pathname. The flags argument determines the file access mode and file status flags.
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* `read`
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* `ssize_t read(int fd, void *buf, size_t count);`
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* Reads up to count bytes from file descriptor fd into the buffer starting at buf.
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* `close`
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* `int close(int fd);`
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* Closes the file descriptor fd.
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* `fork`
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* `pid_t fork(void);`
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* Creates a new process by duplicating the calling process.
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### `<sys/wait.h>`
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* `wait`
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* `pid_t wait(int *wstatus);`
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* Suspends execution of the calling process until one of its children terminates.
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* `waitpid`
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* `pid_t waitpid(pid_t pid, int *wstatus, int options);`
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* Suspends execution of the calling process until the child specified by pid changes state.
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* `wait3`
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* `pid_t wait3(int *wstatus, int options, struct rusage *rusage);`
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* Similar to wait, but also returns resource usage information.
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* `wait4`
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* `pid_t wait4(pid_t pid, int *wstatus, int options, struct rusage *rusage);`
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* Similar to waitpid, but also returns resource usage information.
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### `<signal.h>`
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* `signal`
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* `void (*signal(int signum, void (*handler)(int)))(int);`
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* Sets a function to handle signal signum.
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* `sigaction`
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* `int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);`
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* Examines and changes the action associated with a specific signal.
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* `sigemptyset`
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* `int sigemptyset(sigset_t *set);`
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* Initializes the signal set pointed to by set to exclude all signals.
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* `sigaddset`
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* `int sigaddset(sigset_t *set, int signum);`
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* Adds the individual signal specified by signum to the signal set pointed to by set.
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* `kill`
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* `int kill(pid_t pid, int sig);`
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* Sends the signal sig to the process specified by pid.
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### `<stdlib.h>`
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* `exit`
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* `void exit(int status);`
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* Causes normal process termination and returns an exit status to the host environment.
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### `<sys/stat.h>`
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* `stat`
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* `int stat(const char *pathname, struct stat *statbuf);`
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* Retrieves information about the file pointed to by pathname and fills in the stat structure.
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* `lstat`
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* `int lstat(const char *pathname, struct stat *statbuf);`
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* Similar to stat, but does not follow symbolic links.
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* `fstat`
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* `int fstat(int fd, struct stat *statbuf);`
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* Retrieves information about the file referred to by the open file descriptor fd.
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### `<unistd.h>`
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* `unlink`
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* `int unlink(const char *pathname);`
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* Deletes a name from the filesystem.
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* `pipe`
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* `int pipe(int pipefd[2]);`
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* Creates a pipe, a unidirectional data channel that can be used for interprocess communication.
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* `dup`
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* `int dup(int oldfd);`
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* Duplicates the file descriptor oldfd.
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* `dup2`
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* `int dup2(int oldfd, int newfd);`
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* Duplicates oldfd to newfd, closing newfd first if necessary.
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* `execve`
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* `int execve(const char *pathname, char *const argv[], char *const envp[]);`
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* Executes the program referred to by pathname.
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* `getcwd`
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* `char *getcwd(char *buf, size_t size);`
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* Gets the current working directory and stores it in the buffer pointed to by buf.
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* `chdir`
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* `int chdir(const char *path);`
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* Changes the current working directory to the directory specified in path.
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### `<dirent.h>`
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* `opendir`
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* `DIR *opendir(const char *name);`
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* Opens a directory stream corresponding to the directory name, and returns a pointer to the directory stream.
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* `readdir`
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* `struct dirent *readdir(DIR *dirp);`
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* Reads the next directory entry from the directory stream pointed to by dirp.
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* `closedir`
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* `int closedir(DIR *dirp);`
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* Closes the directory stream associated with dirp.
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### `<string.h>`
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* `strerror`
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* `char *strerror(int errnum);`
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* Returns a pointer to the textual representation of the error number errnum.
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* `perror`
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* `void perror(const char *s);`
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* Prints a descriptive error message to stderr.
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### `<unistd.h>`
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* `isatty`
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* `int isatty(int fd);`
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* Tests whether fd is an open file descriptor referring to a terminal.
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* `ttyname`
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* `char *ttyname(int fd);`
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* Returns a pointer to the null-terminated pathname of the terminal associated with fd.
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* `ttyslot`
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* `int ttyslot(void);`
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* Returns the index of the current user's terminal in the user accounting file.
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### `<sys/ioctl.h>`
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* `ioctl`
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* `int ioctl(int fd, unsigned long request, ...);`
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* Manipulates the underlying device parameters of special files.
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### `<stdlib.h>`
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* `getenv`
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* `char *getenv(const char *name);`
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* Searches the environment list for a string that matches the name.
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### `<termios.h>`
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* `tcsetattr`
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* `int tcsetattr(int fd, int optional_actions, const struct termios *termios_p);`
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* Sets the parameters associated with the terminal referred to by fd.
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* `tcgetattr`
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* `int tcgetattr(int fd, struct termios *termios_p);`
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* Gets the parameters associated with the terminal referred to by fd.
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### `<term.h>`
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* `tgetent`
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* `int tgetent(char *bp, const char *name);`
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* Loads the entry for name from the termcap database.
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* `tgetflag`
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* `int tgetflag(const char *id);`
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* Gets the boolean entry for id from the termcap database.
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* `tgetnum`
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* `int tgetnum(const char *id);`
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* Gets the numeric entry for id from the termcap database.
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* `tgetstr`
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* `char *tgetstr(const char *id, char **area);`
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* Gets the string entry for id from the termcap database.
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* `tgoto`
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* `char *tgoto(const char *cap, int col, int row);`
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* Returns a cursor addressing string for the given capability cap.
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* `tputs`
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* `int tputs(const char *str, int affcnt, int (*putc)(int));`
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* Outputs the string str with padding.
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