Develop ls, with the -l -r -R and -a options, and
with only malloc, free, write, stat, ctime, time, getpwuid, getgrgid,
readdir, opendir and closedir.
From Speedrunning code, the 3 things I re-learnt while recoding a basic ls in C
I ended up with a mostly functional ls in 526 lines of uncommented
ANSI C89. I did not implement the "-R" recursive listing. My ls
differs a little from GNU ls with respect to output file names
when invoked like ls somedirectory.
I worked on this from July 22, 12:30pm to about July 26, 7:15pm, which is just about 4.25 days. I did ordinary things along with that coding, like job, sleeping, household chores, cooking.
After subtracting sleeping, job, etc, I guess I spent between 12 and 16 hours on this. I believe the original author said he spent 5 hours on it. He ended up with 520 lines of C. I did not look at his code until after I finished mine, but there's a remarkable similarity to the designs. We both used linked lists to hold file names and then process the lists.
The nodes of the list are remarkably similar, too.
Assus's:
struct ChainedList
{
struct ChainedList *next;
char *file_name;
struct stat *stats;
};
Mine:
struct filename_node {
char *filename;
struct stat sb;
struct filename_node *prev;
struct filename_node *next;
struct filename_node *contents;
int on_command_line;
};
I used a doubly-linked list so I could sort (and reverse sort for "-r"
flag) the list easier. We even had some functions named the same:
sort_list(), free_list(), print_list().