Reference

Log in to a remote Linux server (e.g., attu)

Print current working directory

Change working directory

List files in working directory
(relevant flags: -a -l -r)

Bring up manual for a command

Log out of shell

Converts standard input to command line arguments
(relevant flags: -d)

Allows for the output of a command to be redirected to both a file and stdout

Clears all output from console

Output the system date

Output a text calendar

Print information about the current system

List files in working directory

Print current working directory

Change working directory

Make a new directory

Remove the given directory (must be empty)

Copy a file
(relevant flags: -i)

Move a file (also used to rename files)
(relevant flags: -i)

Remove the given file
(relevant flags: -f -r)

Create empty file, or change time-modified

Change permissions for filename (e.g., give owners/group read/write, others).
Example: chmod ug+rw,o-rwx file.sh

Change permissions for filename using octal codes. Digits correspond to owner(u), group(g), others(o) respectively (+4 for read, +2 for write, +1 for execute).
Example: chmod 660 file.txt

Sets the default permissions of files, calling umask similarly to chmod with octal will remove those permissions for newly created files (start with a leading 0 to indicate base 8 e.g. umask 0022)

Print contents of a file

Output file contents, one page

Output file contents, one page

Output number of lines of start of file
(relevant flags: -n)

Output number of lines of end of file
(relevant flags: -n)

Count words, characters, lines in a file
(relevant flags: -l -w)

Search given file for pattern
(relevant flags: -E -i -v)

Sort input or file, line based
(relevant flags: -f -r)

Strip duplicate adjacent lines

Search filesystem
(relevant flags: -type)

Remove section from each line of file

This will replace all matches of REGEX in the given file with TEXT and output it to the console.

Print your username

Print user ID and group membership

List logged-in users (short)

List logged-in users (long)

Print information about users

Print group membership

Create a group

Delete a group

Modify a group

Assign to group

Changes all files recursively starting in the current directory to be owned by

List processes being run
(relevant flags: -u)

Show process statistics

Terminate process by PID

Terminate process by name

Compile ClassName

Run ClassName

Run or compile other files in different languages!

References the working directory

References the parent of working directory

username's home directory

Your desktop

Root directory that contains all directories

Applications/programs (i.e. binaries)

Hardware devices

Configuration files

Contains user's home directories

Running programs (processes)

Temporary files

Universal system resources

Directories have the same permissions as files but read determines viewing privileges, write determines add/delete file privileges, and execute determines whether a user can enter the directory.

Very simple editor

More advanced text-editor

More advanced text-editor

Write (save) the current file

Write (save) the current file and exit

Quit, ignoring all changes

Go into insert mode

Go back to normal mode

Move cursor left, down, up, right

Undo last change

Delete character

Read a file into emacs

Save a file to disk

Exit emacs

Search forward

Search backwards

Scroll to next screen

Scroll to previous screen

Undo

At top of file, tells the command line how to interpret your file

Gives script.sh execute permissions so it can be run with ./script.sh

Creates a variable (no spaces on either side of = sign) (variable names are case sensitive)

Variables are referenced using the $ operator (output":" I am taking 391)

Single quotes will not expand variables (output":" I am taking $CLASS)

The output of running a command can be saved to a variable and referenced later

Name of the script

First, second, third arguments

Number of arguments

List of all arguments

Use let expression to do arithmetic (bash supports multiplication, division, addition, and subtraction)

Other way to do arithmetic, must have spaces in between operations!

For loop syntax, begins with do and ends with done. Semicolon is the same thing as a new line.

Iterates over all of the files in the current directory by iterating over output of ls

If statement basic syntax. Boolean expression must be surrounded by [ ] with spaces on either side.

greater than, less than, greater than or equal to, less than or equal to, equals, not equals

And operator. Can also be written (if [ expr1 ] && [ expr2 ]; then)

Or operator. Can also be written (if [ expr1 ] || [ expr2 ]; then)

Negates expr1

Test if string is equal (=) or not equal (!=)

Test if a string is empty (-z) or nonempty (-n)

Test if a file (-f) or directory (-d) exists

Test if a file exists and is readable (-r), writeable (-w) or executable (-x)

Variable containing exit status of previously run program. It will be 0 if the program executed correctly, or not 0 if it failed.

Execute command and read its standard input from the contents of filename instead of from the console.

Execute command and redirect its standard output to the given filename

Execute command and redirect its standard error to the given filename

Execute command and redirect its standard error to standard output

Execute command, redirect standard error to standard output, and redirect standard output to filename

Execute command1 and send its standard output as standard input to command2.

Execute command1, then execute command2

Execute command1, and if it succeeds, then execute command2

Execute command, then place the output string literally into the given context i.e. javac $(find -name "*.java")

Creates alias for (do NOT put spaces surrounding the equals)

Everytime you log in to a shell (i.e. by ssh-ing into attu or logging into your computer), the commands in ~/.bash_profile are run

Everytime you launch a non-login shell (i.e. by launching a new terminal) the commands in ~/.bashrc are run.

Stores the path to all directories which the system will look for programs to run. If a path is in $PATH and contains a file named , will be run when you type

Prepend a directory to your $PATH (directory will be looked through first for a filename matching when )

Append a directory to your $PATH (directory will be looked through last for a filename matching when )

Copy a git repository

Adds file contents to staging area

Same as git add

Takes a snapshot of staging area and creates a commit

View status of files in working directory and staging area

Show difference between staging area and working directory

Show commit history

Fetch from remote repository and try to merge

Push local repository to remote repository

Create a new branch with the name branch name

Switch to the branch branch name

Merges the feature branch into the current branch checked out

View the commit history, and where HEAD and master are located. Flags unnecessary

Matches any character

Matches start of line

Matches end of line

Matches start of word

Matches end of word

Escape the following character

(Flag to grep) Match case insensitively

Logical or operator (match this character set or that character set)

Matches zero or more of the preceding character set

Matches one or more of the preceding character set

Matches zero or one of the preceding character set

Group characters together

Character set

Negate character set

Matches all lowercase letters

Matches all uppercase letters

Matches all digits

Back references the same characters captured in an earlier grouping (specified by the number)

Specify how many occurrences of a match we want. Can be an exact number (e.g. {N}) or a range of numbers (e.g. {MIN,MAX}).