The echo command allows you to print something out to the terminal Now that you understand a bit about the basic command structure, here are a few basic commands that you can use. # -5 sets N to be 5, so the last 5 lines of the output are printed out Basic Commands # the output is piped to the tail command, which prints the last N lines # this runs python, passing in a script called 'read_file.py' This becomes very useful when we begin using new commands as well as chaining them. The pipe character ( | ) redirects the output of the command to the next command in the chain. # output will not be printed to the terminal. # it also makes the output write to a file called 'results.txt' # this runs python, passing in a script called 'run_calculation.py' It is useful for a variety of reasons that we will look into later. This allows input redirection, meaning you can use the contents of a file as the input for the command. # '/home/mimir/project1' is the argument to the 'cd' command input: These are the main variables passed to the command. These are the arguments passed to the command ( argument 0 through argument N), usually a single argument but can be a large list of arguments. # '-alF' on the 'ls' command corresponds to the following flags: This can cause many different things to happen based on the options you select, check the man pages for the command for more info. These are options (also known as flags) that cause a command to run slightly differently. # 'pwd' prints the name and location of the working directory options: # 'ls' lists the current directory and the files within it This can be a variety of words and phrases depending on the operating system you use. Let's look at what the basic command structure looks like:Īll commands that you will run via the command line interface will follow a similar structure:Ĭommand ( output) (| pipe?) We can accomplish this by typing in our commands, and hitting the Enter key to execute the line. The way we will use Bash is by calling commands in order to accomplish what we want. REPLs exist for many different languages, and for many different purposes. Print the results in the way that the user or shell specifies REPL is an acronym for Read, Evaluate, Print, and Loop:Įvaluate the user input, running commands and generating the output Shells are simple interactive computing environments (also known as a REPL), generally text only, that can be used to take user input, evaluate it, and return the results to the user. If you close your terminal window you can open a new one using the file menu.īash is a type of shell for the Unix-type operating system. This is where you will be typing in bash command.
The terminal is the area highlighted by the orange box above.
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