recode-fa23

BASIC LINUX COMMANDS

FILES & NAVIGATING

ls: directory listing (list all files/folders in current dir)
ls -l: formatted listing
ls -la: formatted listing including hidden files
cd dir: change directory to dir (dir will be directory name)
cd ..: change to parent directory
cd ../dir: change to dir in parent directory
cd ~: change to home directory
pwd: show current directory
mkdir dir: create a directory dir
rm file: delete file
rm -f dir: force remove file
rm -r dir: delete directory dir
rm -rf dir: remove directory dir
cp file1 file2: copy file1 to file2
mv file1 file2: rename file1 to file2
mv file1 dir/file2: move file1 to dir as file2
touch file: create or update file
cat file: output contents of file
cat > file: write standard input into file
cat » file: append standard input into file
tail -f file: output contents of file as it grows

NETWORKING

ping host: ping host
whois domain: get whois for domain
dig domain: get DNS for domain
dig -x host: reverse lookup host
wget file: download file
wget -c file: continue stopped download
wget -r url: recursively download files from url
curl url: outputs the webpage from url
curl -o meh.html url: writes the page to meh.html
ssh user@host: connect to host as user
ssh -p port user@host: connect using port
ssh -D user@host: connect & use bind port

PROCESSES

ps: display currently active processes
ps aux: detailed outputs
kill pid: kill process with process id (pid)
killall proc: kill all processes named proc

SYSTEM INFO

date: show current date/time
uptime: show uptime
whoami: who you’re logged in as
w: display who is online
cat /proc/cpuinfo: display cpu info
cat /proc/meminfo: memory info
free: show memory and swap usage
du: show directory space usage
du -sh: displays readable sizes in GB
df: show disk usage
uname -a: show kernel config

COMPRESSING

tar cf file.tar files: tar files into file.tar
tar xf file.tar: untar into current directory
tar tf file.tar: show contents of archive

PERMISSIONS

chmod octal file: change permissions of file
chmod 777: rwx for everyone
chmod 755: rw for owner, rx for group and world

SOME OTHERS

grep pattern files: search in files for pattern
grep -r pattern dir: search for pattern recursively in dir
locate file: find all instances of file
whereis app: show possible locations of app
man command: show manual page for command

ADDITIONAL COMMANDS

sudo: ‘super user do’ - execute a command as the superuser
| (pipe): Takes the output of one command and uses it as input for another, e.g.:
```
ls dir | grep file # outputs file name if file is in directory
```

* (star): wildcard - represents zero or more characters, e.g.:

mv 'Screen\ Shot*.png' ~/.Trash # move all screen shots in the current directory to the trash (on Mac)