30-45 minutes
Basic command line class.
Teach people some handier tools for advanced file searching and processing
Participants will be able to::
- Find files.
- Parse file contents with sed and awk.
- Modify the command prompt info.
- Redirect input and output streams
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History
historycommandhistory|grep cat
Shortcut to search backwards through history Ctrl+R (on a mac) then type string like "cat"
- Tabs - contents and relation to each other Just like a browser, Mac Terminal supports multiple tabs to do multiple things at once.
Cmd + T to open a new tab
- Piping commands together
You can chain commands.
cat *.txt |grep error | wc -l
Print all text files, searching for only lines containing "error", and print a count.
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Output Write to a file with > # this overwrites Append it to a file with >> #this appends to the end
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Permissions user / group / other bit masks
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Command line Options Programs can use long and/or short options.
grep -l important * grep --files-with-matches important *
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Which command See what version of a program is in use.
which npmwhich python -
Special characters Some special characters must be treated differently to use literally. & is a special character - should be quoted to use in a string
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Quotes within quotes require backslash echo "My name is "Lin""
List of basic commands
find - find files
grep - find things inside files
cut - remove sections from each line of files
awk - pattern-directed scanning and processing language
sed - stream editor for filtering and transforming text
tr - translate, squeeze, and/or delete characters from standard input, writing to standard output
alias - allow a string to be substituted for a word when it is used as the first word of a simple command
export - export/set a new environment variable
xargs - execute arguments
- BashGuide
- Filenames and Pathnames in Shell: How to do it Correctly
- An Awk Primer/Awk Command-Line Examples
- I/O Redirection
Let's say we remember part of the path of a file but nothing else. We can use find like so (remember to man find): find / -path "part/you/recall"
List of advanced commands
echo - print some arguments
pushd - push directory
popd - pop directory
env - look at your environment
export - export/set a new environment variable
find - find files
wc - wordcount (word & line count)
sort - sort data
cut - remove sections from each line of files
hostname - my computer’s network name
xargs - execute arguments
sudo - become a super user root (DANGER - only use when necessary)
chmod - change permission modifiers
chown - change ownership
apropos - find what man page is appropriate
awk - pattern-directed scanning and processing language
sed - stream editor for filtering and transforming text
This lesson helps you create an executable script.
Open Terminal.
Create a small file called 'lunch' containing
#!/bin/bash
lunch=$1 # read in user input
echo $lunch is for lunch, along with $FAVEFOOD.
Make it executable.
chmod a+x lunch
Run it.
./lunch
./lunch Soda
Now create a file containing some foods.
echo "mac & cheese" > foods.txt
echo dim sum >> foods.txt
echo an apple >> foods.txt
Edit lunch to use this file
#!/bin/bash
lunch=$1 # read in user input
echo $lunch is for lunch, along with $FAVEFOOD.
echo We also offer:
cat foods.txt
Hold down COMMAND and hit the spacebar.
When the search bar appears type: terminal
The terminal is the black box that appears on the screen
In the dock, you can control-click and keep inside of dock
Greg's Wiki is full of common mistakes (e.g. why you shouldn't parse ls).
Is it relevant to them how
Apprentices can try to do this other thing.
Summarize to each other, make a cheat sheet, take a quiz, do an assignment, or something else that helps assess understanding.