Command Line Crib Sheet

Commands, Special Symbols, and Keyboard Shortcuts

!	exclamation point/bang	Shortcut for repeating a command—!<command number> repeats the command with that number (as listed by the history command); !! repeats the last command
/	forward slash	Separates successive folders in a cd command
<	input redirect/less-than sign	Specifies that the content of a file (to the right of the <) should serve as the input into the command on the left
>	output redirect/greater-than sign	Specifies that the result of a program (to the left of the <) should be saved into the file on the left
	pipe	becomes the input into the program to the right
~, ~username	tilde	Shortcut for a user’s home folder; when immediately followed by a username (no spaces), this represents that user’s home folder
cat <filename>	concatenate a file (long story)	Display the contents of the given file
cd <directory or folder>	change directory	Changes the current directory/folder to the one indicated in the command
cp -i <file to copy> <destination of copy>	copy file	Copies the given file to the given destination; the -i stands for “interactive,” meaning that cp will ask permission if a file at the destination might get replaced
Ctrl-C		“Panic” key—bail out of the current program and jump back to the command line
Ctrl-D		“End input” key—ends a program when using it in “practice” mode (where you type the data that you want it to manipulate)
exit	exit	Log out of your command line session.
history	history	Lists the commands you have typed so far
left/right arrow keys		Go backward/forward across current command (allowing you to edit it)
logout	logout	Log out of your command line session.
ls	list files	Display the files in the current directory; adding a -F to the command (i.e., ls -F) adds a symbol to the file listings indicating their type
mv -i <file to move or rename> <new location or name of the file>	move or rename a file	Move or rename a file; as with cp, the -i is an “interactive” mode that asks permission if something might get replaced
pwd	print working directory	Displays the directory/folder in which you are working; the command prompt also shows this
Tab key	autocomplete	Lists possible matching choices if there is more than one, or autofills immediately if there is only one match
up/down arrow keys		Go back and forth through command history

Search Pattern Symbols (a.k.a. regular expression or regex symbols)

Used by grep, sed, and XMLPipeDB Match to indicate what patterns to find.

.	Single-character wildcard	Matches any character
*	Zero or more	Matches zero or more of the symbol that precedes it
^	Beginning of line	Matches the pattern after it only if it appears at the beginning of a line
$	End of line	Matches the pattern before it only if it appears at the end of a line
+	One or more	Matches one or more of the symbol that precedes it
\"	Double-quote character	Matches a double-quote in a line; the extra backslash (\) is needed so that this quote is not confused for indicating the end of the search pattern
\d	Number 0-9 (i.e., digit)	Matches any single-digit number
\w	Letter or number (i.e., something that would appear in a word)	Matches any letter or number, but not punctuation, spaces, or other symbols

sed Search/Replace Directives

To be written.