Linux: files and permissions

Navigating, copying and finding files, disk usage, permissions and ownership.

Navigating and viewing

List files with details and hidden files

ls -lah

List files sorted by modification time

ls -lt

Directory tree (2 levels)

tree -L 2

Show the end of a file and follow it

tail -f <file>

Show the last 100 lines

tail -n 100 <file>

Page through a file

less <file>

Inside less: / to search, n for next match, G to jump to the end, q to quit.

Copy a directory recursively

cp -r <source> <destination>

Copy preserving permissions and timestamps

cp -a <source> <destination>

Move or rename

mv <source> <destination>

Create nested directories

mkdir -p <path>

Delete a directory with its contents

rm -rf <path>

There is no trash bin — double-check the path.

Create a symbolic link

ln -s <target> <link_name>

Find files by name

find <path> -name '*.log'

Find files larger than 100 MB

find <path> -type f -size +100M

Find files modified in the last 24 hours

find <path> -type f -mtime -1

Delete files older than 7 daysadvanced

find <path> -type f -name '*.log' -mtime +7 -delete

Run it without -delete first to see what will be removed.

Free space on mounted filesystems

df -h

Size of a directory

du -sh <path>

Biggest items in a directory

du -sh <path>/* | sort -rh | head -20

Free inodesadvanced

df -i

A disk can be “full” with free space left if it runs out of inodes (many tiny files).

Make a script executable

chmod +x <file>

Set permissions numerically (rw-r--r--)

chmod 644 <file>

Change owner recursively

chown -R <user>:<group> <path>

Show numeric permissions of a fileadvanced

stat -c '%a %U:%G %n' <file>

On macOS: stat -f '%Lp %Su:%Sg %N' <file>