Files and Directories Without Regret

Four commands cover almost everything you'll do to files on a server:

mkdir dirname          # make a directory
touch filename          # create an empty file (or bump its timestamp)
cp src dst               # copy
mv src dst               # move or rename - same command, same idea
rm filename               # delete

rm has no undo button, no trash can, and by default it never asks "are you sure?" The flags -r (recursive - go into every subfolder too) and -f (force - never ask for confirmation) combine into rm -rf, which deletes an entire folder and everything inside it, instantly, with no warning. This is one of the most common ways people accidentally delete something important on Linux. It's not dangerous because it's complicated - it's dangerous because it's fast and gives you no chance to change your mind.

Reading a directory listing properly

A colleague deployed to ~/deploy/ and left it a wreck:

cd ~/deploy
ls -la

total 16
drwxrwxr-x 3 laborant laborant 4096 Sep 22 03:43 .
drwxr-x--- 9 laborant laborant 4096 Sep 22 03:43 ..
-rw-rw-r-- 1 laborant laborant   25 Sep 22 03:43 app.conf
drwxrwxr-x 3 laborant laborant 4096 Sep 22 03:43 archive
-rw-rw-r-- 1 laborant laborant    0 Sep 22 03:43 old-2026-01-01.tmp
-rw-rw-r-- 1 laborant laborant    0 Sep 22 03:43 old-2026-01-02.tmp
-rw-rw-r-- 1 laborant laborant    0 Sep 22 03:43 old-2026-01-03.tmp

The first character of each line tells you what kind of entry it is: - for a regular file, d for a directory. So app.conf is a real file, archive is a directory, and the three old-*.tmp files are all real files too - each one 0 bytes, meaning genuinely empty, left over from some earlier abandoned attempt. One file matters (app.conf), one directory needs a look inside (archive), and three files are pure junk.

Wildcards

The character * stands in for "any number of any characters." So old-*.tmp matches every file whose name starts with old- and ends with .tmp, no matter what's in between - it matches all three junk files above in one shot. This lets you act on many files with one command, which is powerful, but also means it's easy to delete more than you meant to. So check first, delete second:

ls old-*.tmp      # look at exactly which files the wildcard matches
rm old-*.tmp        # only delete them once you've confirmed the list looks right

Links

A hard link, made with ln target linkname, is a second name pointing at the exact same data on disk. If you delete the original name, the data is still there, safe, under the other name. A symbolic link (or "symlink"), made with ln -s target linkname, is different - it's a small separate file that just contains a path, like a signpost pointing somewhere. If you delete the thing it points at, the symlink is left pointing at nothing. Symlinks are what you'll actually use day to day, most often to create a "current version" name that always points at whichever file is the active one right now.

Clean it up

Remove the junk, remove the now-empty archive/empty-leftover directory, and set up a current pointer to the real config:

rm old-*.tmp
rmdir archive/empty-leftover
ln -s app.conf current
ls -la

total 16
drwxrwxr-x 3 laborant laborant 4096 Sep 22 03:43 .
drwxr-x--- 9 laborant laborant 4096 Sep 22 03:43 ..
-rw-rw-r-- 1 laborant laborant   25 Sep 22 03:43 app.conf
drwxrwxr-x 2 laborant laborant 4096 Sep 22 03:43 archive
lrwxrwxrwx 1 laborant laborant    8 Sep 22 03:43 current -> app.conf

Two changes prove the cleanup worked: the three old-*.tmp lines are gone, and there's a new line starting with l (for "link"), current -> app.conf, showing the symlink and exactly what it points at. Confirm what it actually resolves to:

readlink -f current

/home/laborant/deploy/app.conf

readlink -f follows the symlink and prints the real, absolute path it leads to - proof current genuinely points at app.conf, not at nothing.