TopolearnThese dozen commands are what you type most on any Linux machine.
Paths are absolute when they start with / and relative to the current directory otherwise. . is the current directory, .. its parent and ~ your home. pwd prints where you are, cd dir moves, cd alone goes home and cd - returns to the previous directory.
ls lists a directory: -l long format (permissions, owner, size, date), -a includes hidden dotfiles, -h human-readable sizes, -t sorts by time. File names are case-sensitive, and extensions mean nothing to the system.
Managing files:
mkdir -p a/b/ccreates nested directories,touch fcreates an empty file,cp src dstcopies (-rfor directories,-ato preserve permissions and times),mv src dstmoves or renames,rm fdeletes,rm -r dirdeletes recursively,rmdirremoves empty directories.
There is no trash can: rm is permanent. Use -i to be asked, double-check globs with ls first, and never run rm -rf with a variable that might be empty.
find searches a tree by name, type, size or age: find . -name '*.log' -mtime +7 lists logs older than a week; add -delete or -exec to act on them. tree (if installed) draws a directory tree.
Example
cd "$(mktemp -d)"
pwd # /tmp/tmp.Xyz
mkdir -p project/src/utils # -p: create parents, no error if present
touch project/README.md
cp project/README.md project/README.bak
mv project/README.bak project/notes.md # move = rename
ls -la project # long listing, hidden files included
cp -r project project-copy # -r for directories
rm -r project-copy # recursive delete: there is no undo
find . -name '*.md' | sort # ./project/README.md ./project/notes.md
find . -type d -empty # ./project/src/utils
cd project/src && cd ../.. # .. is the parent directory
cd - >/dev/null && pwd # back to the previous directoryRemember
- Absolute paths start with /; . is here, .. is the parent, ~ is home
- cp -r and rm -r for directories; mv also renames
- rm is permanent; find searches by name, type, size and age
Watch out for
- Running
rm -rf "$DIR"/*when DIR is empty, which expands to /*.