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UNIX Commands Cheatsheet
Another day, another cheatsheet?
Well, not trying to bombard the web with yet another cheatsheet, but I thought that this would be a good opportunity to refresh myself on UNIX and LINUX commands. I do not have a background in Computer Science, so I am just picking up these topics along the way to acquire a more well-rounded background knowledge base.
I'm not going to get into the details of Unix (see wiki here)... but I mostly need to have basic knowledge of the commands to navigate the terminal in Mac OS, most developers do.
The statement below kind of sums it up:
Mac OS X is a Unix OS and its command line is 99.9% the same as any Linux distribution. Bash is your default shell and you can compile all of the same programs and utilities.
Below is the lists of useful commands but keep in mind that I run MacOs with zsh so there might be some subtle differences in the command or command flags.
Basic System Commands
| Command | Description | Example Usage |
|---|---|---|
| man | help docs, manual on the command | man echo |
| whoami | the current user | whoami |
| cal | display current month calendar | cal |
| date | display current date | date |
| history | shows the history list of commands used | history |
| history | > -N, a flag to show last N commands (zsh) | history -10 |
When in man mode, pressing q will quit and close out that mode and pressing spacebar will advance to next section.
Folders and File Commands
| Command | Description | Example Usage |
|---|---|---|
| pwd | present working directory, where you current are | pwd |
| mkdir | make a folder with given folder name | mkdir myFolder |
| mkdir | make multiple folders with that begin with same names | mkdir folder1 folder2 |
| mkdir | simplify making multiple folders that begin with same names | mkdir folder3 |
| mkdir | > -p, flag to make parent folder with child folder inside | mkdir -p parentFolder/childFolder |
| rmdir | remove the given folder | rmdir myFolder |
| rmdir | remove multiple folders that begin with the same names | rmdir folder* |
| touch | create a file with given file name | touch myFile.txt |
| rm | remove the given file | rm myFile.txt |
| ls | list the folders and files at present working directory | ls |
| ls | > -l, flag to show long format | ls -l |
| ls | > -a, flag to show all files, including hidden | ls -a |
| ls | > -t, flag to show time, descending | ls -t |
| ls | > -r, flag to show in reverse order | ls -r |
| cp | copy a file or folder into a target folder | cp myFile.txt myFolder |
| cp | > -r, flag for recursive, takes all the files in a folder | cp -r myFolder1 myFolder2 |
| mv | move or cut and paste, move folder into target folder | mv myFolder1 targetFolder |
| mv | move multiple files into target folder | mv {file1.txt,file2.txt} targetFolder |
| mv | renames a file name to another file name | mv oldFileName.txt newFileName.txt |
CAT Commands
Concatenate (CAT) command is used frequently to read data from a file and gives the content as output.
| Command | Description | Example Usage |
|---|---|---|
| cat | output content of file | cat myFile.txt |
| cat | > -n, flag to show line numbers | cat -n myFile.txt |
| cat | create file and allow insertion of data in line | cat > myFile |
| cat | copy file content into another file (overwrite into file) | cat fileContent > newFile |
| cat | copy by merging of two files | cat file1 file2 > file1n2 |
| cat | copy file content into another file (append into file) | cat fileContent >> newFile |
GREP Commands
Global search for regular expression and printout, global-regular-expression-print (grep), searches a file for a particular pattern of characters, and displays all lines that contain that pattern.
GeeksForGeeks has a collection of great resources with examples on the grep command as well as other Unix commands.
| Command | Description | Example Usage |
|---|---|---|
| grep | searches the file given a search term | grep "searchTerm" fileName |
| grep | > -i, flag to ignore case sensitive | grep -i "searchTerm" fileName |
| grep | > -n, flag to also return the line number of found | grep -n "searchTerm" fileName |
| grep | > -l, flag to return fileName if search found | grep -l "searchTerm" fileName |
| grep | > -w, flag that matches exact word | grep -w "searchTerm" fileName |
| grep | > -v, flag that ignores the search term, returns inverse | grep -w "searchTerm" fileName |
| grep | > -c, flag to display the count of search matches | grep -c "searchTerm" fileName |
| grep | chaining flags to search ignore case w/ line number | grep -in "searchTerm" fileName |
| egrep | searches a file given multiple search terms | egrep "firstTerm|secondTerm" fileName |
Other Commands of Interest
| Command | Description | Example Usage |
|---|---|---|
| > | redirects standard output | grep "searchTerm" fileName > newFile |
| >> | redirects and appends standard output | grep "searchTerm" fileName >> newFile |
| < | redirects standard input | grep "searchTerm" < fileName |
| | | pipe symbol, chain two or more commands | ls -l | grep -i folderName |
| find | find in current directory and all subdirectory | find . | grep fileName |
| diff | display differences in two files | diff fileOne fileTwo |
| diff | > -y, flags to show all lines compared side by side | diff -y fileOne fileTwo |