Some missions ideas

using ls -l and some other common options

ls * vs ls -d *

using less / more to paginate the output of a command

meaning of the PATH variable

symbolic links ("Make a secret passage from one room to another.")

using sort / uniq

file command

diff and/or cmp

search through the history with C-r

history of commands

more missions using shell patterns [...] and [^...] (or [!...] as specified by POSIX, but this interacts with bash' history expansion)

mission using */* patterns to explain that / are not captured by wildcards

simple regular expressions and grep

create empty files with touch, update modification date

dealing with strange files: spaces (quoting / escaping), starting with a dash (using --), etc.

scripting: for loops on files

yes command (not POSIX) and pipes

pushd / popd

comm to compare before / after file

paste (restore a torn treasure map)

join

wget / curl

tar / zip

• Idea: receive/send a package (archive = packaging).

fuser / lsof

print prime numbers less than N with a combination of seq / factor / grep / cut

only activate completion once the first appropriate mission has been completed (put bind 'set disable-completion' on in the first mission's gshrc, and bind ... of in some mission' treasuse.sh)

"summary missions" to practice what has been learnt at the end of the missions/basic mission group. We could ask the player o tidy up the pantry, initially filled with a big mess of files (fruits, cheese, meat, wine, trash, ...) and the player would have to organise everything into a specified directory structure: fruits in "barrels", cheese on "shelves", get rid of trash, ...

manage an inventory (or the Chest) with aliases:

• alias inventory='ls ~/Forest/Hut/Chest | nl to show the inventory,
• alias pick='mv -t ~/Forest/Hut/Chest to pick an item (NOTE: it probably requires GNU's mv with option -t)
• alias drop='...' to drop an item at the current location (NOTE: that's probably better to use a function for that, no?)