Creating and organising files

Not running Starting usually ~20 s

Step 9 of 10 · lab · 15 min

Tidy up a directory

Clear out what a build left behind and put the files in their places without losing the working data.

Situation

A build left temporary *.tmp files and a leftover old directory in ~/workspace, and the notes are mixed in with the tables. A colleague asks you to tidy it up. The *.csv tables are working data: they must not be lost.

Task

Make it so that:

no temporary *.tmp files are left, neither in ~/workspace nor in its subdirectories;
the ~/workspace/old directory is gone;
the *.txt notes sit in a ~/workspace/text subdirectory;
every *.csv table sits directly in ~/workspace, with its contents unchanged.

Lab · on your own

No commands are given in this lab: type them in the terminal yourself. Goals are checked on the machine after every command.

Goals

0 of 4

No *.tmp files in ~/workspace or its subdirectories — not done yet
Directory ~/workspace/old is gone — not done yet
The *.txt notes sit in ~/workspace/text — not done yet
Every *.csv table sits in ~/workspace with its contents unchanged — not done yet

Ctrl+Enter

Starts the machine node1 · Ubuntu 24.04

The machine is starting

Hints

0 of 3

Report a problem

Lab goals

0 of 4

No *.tmp files in ~/workspace or its subdirectories — not done yet
Directory ~/workspace/old is gone — not done yet
The *.txt notes sit in ~/workspace/text — not done yet
Every *.csv table sits in ~/workspace with its contents unchanged — not done yet

node1 Ubuntu 24.04

Lab goals

0 of 4

No *.tmp files in ~/workspace or its subdirectories — not done yet
Directory ~/workspace/old is gone — not done yet
The *.txt notes sit in ~/workspace/text — not done yet
Every *.csv table sits in ~/workspace with its contents unchanged — not done yet

Files and directories · picked for this lab

rm — remove files and directories

Cheat sheet

$_ — insert into the terminal

rm notes.txt delete a file
rm -i *.log ask about every file
rm -I *.log ask once if there are more than three
rm -r old-project a directory with everything inside
rm -rf build/ no prompts, no errors about missing files
rm -d empty-dir an empty directory (like rmdir)
rm -v *.tmp print each removal
rm -- -file.txt a name that starts with a dash
ls *.log && rm -i *.log look first, then delete

Full list — man rm. In practice -i, -I, -r, -f, -v are enough.

Check a pattern before deleting

bash

ls -d /var/tmp/app/*.cache     # what the pattern matches
rm -v /var/tmp/app/*.cache     # the same, now delete

The shell expands the pattern (see globbing), so ls with the same pattern shows exactly the list rm will get.

Delete old files by age

bash

find /var/log/app -name '*.log' -mtime +30 -print   # list first
find /var/log/app -name '*.log' -mtime +30 -delete  # then delete

rm can't select by date or size — that's find's job.

Guard `rm -rf` against an empty variable

bash

rm -rf -- "${BUILD_DIR:?}"/*   # empty variable → error, not /*

${VAR:?} stops the command if the variable is empty or unset.

Delete a file with a strange name

bash

rm -- '-rf'            # a name with a leading dash
rm -i ./*' '*          # names with spaces — with confirmation
ls -li                 # the inode number in the first column
find . -inum 1234567 -delete   # delete by inode number

rm: cannot remove 'dir': Is a directory

The argument is a directory. rm -d removes an empty one, rm -r one with contents (look inside first: ls -R dir).

rm: cannot remove: Permission denied

You can't write to the directory holding the file. Check ls -ld $(dirname path). System files are removed with sudo rm, but first make sure no package or service needs the file.

rm: remove write-protected regular file?

The file lacks w. rm asks instead of refusing: answer y, or delete with -f if you're sure.

rm: cannot remove: Operation not permitted

The file has the immutable attribute (lsattr file shows i), or it's someone else's file in a sticky directory like /tmp. Clear the attribute with sudo chattr -i file.

Disk space wasn't freed

A process still has the file open: the name is gone, the data isn't. Find the holder with sudo lsof +L1 — see lsof and disk-usage. The space comes back when that process restarts.

Argument list too long

The pattern matched too many files for one command. Delete with find: find . -name '*.tmp' -delete.

There's no recovery

rm doesn't move files to a trash. If a file isn't in a backup or in git, consider it gone. Before a mass delete run ls with the same pattern, or use rm -I.

`rm -rf` with a stray space or an empty variable

rm -rf / tmp/build (an extra space) asks to delete the root. A built-in check guards / (it is dangerous to operate recursively on '/'), but /*, ~ and . have no guard: rm -rf "$DIR"/* with an empty $DIR becomes rm -rf /*. Write "${DIR:?}" and read the whole command before pressing Enter.

Creating and organising files

Situation

Task

Signing in is needed to start the machine

Check a pattern before deleting

Delete old files by age

Guard rm -rf against an empty variable

Delete a file with a strange name

rm: cannot remove 'dir': Is a directory

rm: cannot remove: Permission denied

rm: remove write-protected regular file?

rm: cannot remove: Operation not permitted

Disk space wasn't freed

Argument list too long

There's no recovery

rm -rf with a stray space or an empty variable

Guard `rm -rf` against an empty variable

`rm -rf` with a stray space or an empty variable