ls.md

ls

POSIX 7

List files in directories.

l

Show lots of information:

ls -l

Sample output:

-rw-rw-r-- 1 ciro ciro  4 Feb 25 11:53 a
1          2 3    4     5 6            7

1. file permissions. See permissions
2. for files, number of hardlinks. For directories, it is the number of subdirs + parent + self, the minimum being 2 therefore.
3. owner
4. group
5. size in bytes
6. last modified
7. filename

ls permissions can also have a trailing + in case of ACL: http://serverfault.com/questions/227852/what-does-a-mean-at-the-end-of-the-permissions-from-ls-l

ls is aware if its output goes to a pipe or not. if yes, automatically newline separates it:

ls | cat

One per line:

ls -1

ls a file:

touch a
[ "$(ls a)" = "a" ] || exit 1

ls a dir:

mkdir d
touch d/a d/b
[ "$(ls d)" = "$(printf 'a\nb\n')" ] || exit 1

ls many dirs:

mkdir d
touch d/a d/b
mkdir e
touch e/a e/b
ls d e

-d: list directory names only:

mkdir d
touch d/a d/b
mkdir e
touch e/a e/b
[ "$(ls -d d e)" = "$(printf 'd\ne\n')" ] || exit 1

-lL: when showing symlinks, shows info to what is linked to

Sort

Modification time (newest first):

ls -t

Inode change:

ls -tc

File access:

ls -tu

Reverse sort order:

ls -tr

GNU extensions

-R: recursive

ls -R