Command Shell

You can use a command shell to interact with Amperity.

Basics

Command

Description

Ctrl + a

Move to the beginning of a line.

Ctrl + c

Stop the execution of the current command. Useful if you’ve typed something that will take a while to complete, but need to stop the command.

Ctrl + e

Move to the end of a line.

Ctrl + r

Search through the terminal history.

After typing Ctrl + r start typing the command that you’re looking for and previously used commands will populate based on your search.

To cycle through commands that use the same search term just hit Ctrl + r again.

Option + b

Move back a word. On Mac OS X this requires the Use Option as Meta key setting to be enabled at Terminal > Preferences > Profiles > Keyboard.

Option + f

Move forward a word. On Mac OS X this requires the Use Option as Meta key setting to be enabled at Terminal > Preferences > Profiles > Keyboard.

man

Display the man(ual) page for any command

Use man grep to show you all the different flags and options that you can pass to grep.

https://xkcd.com/1168/

Manipulate files

Command

Description

mv file1.csv file2.csv

Renames file1.csv to file2.csv.

mv file1.csv folder/file1.csv

Moves file1.csv to a directory named ‘subfolder’.

cp file1.csv file2.csv

Makes a copy of file1.csv called file2.csv without modifying the original.

cp -r

Copy all of the files in a folder recursively. You cannot copy the entire contents of a folder without this flag.

rm file1.csv

Remove a file. Make sure you want to delete this file. Deletion from the terminal is permanent.

touch filename.csv

Create a blank file called filenames.

Inspect files

Command

Description

less BigFile.csv

Stream the contents of a file to the screen one window at a time. Ideal for viewing large files since less does not require reading the entire file for display.

head BigFile.csv

Display the first 10 lines of a file

head -n 100

Use the -n flag to display a specific number of rows.

file filename.csv

Outputs basic information about the file format.

Examples of output (that Amperity can easily ingest).

ASCII text, with CRLF line terminators.

UTF-8 Unicode text, with CRLF line terminators.

wc filename.csv

Count the number of words in a file.

Use the -l flag to display the number of lines in the file.

cat

Display the entire contents of a file to stdout. Useful for piping the contents of a file into another command.

grep “searchterm” filename.csv

Will search the file for “searchterm” and return any results.

Use the -C flag in conjunction with a number to show the number of lines before and after a result Ex: -C5 will show 11 lines in total.

Use the -E flag will to pass regex to grep rather than a simple search string.

Move files

Command

Description

scp file.txt prod:/mnt/folder/file.txt

Copy myfile.txt from your local machine to a remote machine.

tmux

Command

Description

tmux new -s SessionName

Start a new tmux session.

tmux a -t SessionName

Connect to a previously created named tmux session.

tmux ls

List all tmux sessions.

Ctrl + b, d

Detach from tmux while in an active session.

Ctrl + b, ?

Show all tmux options

Ctrl + [

Move around the terminal with the arrow keys.

Redirect stdout

Command

Description

>

After a command will take the output of that command and write it to a file. For example:

$ head BigFile.csv > SmallFile.csv

will take the first 10 lines from BigFile.csv and write them to the new file SmallFile.csv. If SmallFile.csv exists it will be overwritten. If it does not exist it will be created.

>>

Can be used to concatenate results onto a file. For example:

$ head MediumFile.csv >> SmallFile.csv

will take the first 10 lines from MediumFile.csv and append them to SmallFile.csv.