Code / Command Line & Git / Unit 2: Making & changing files

Write and read files फ़ाइल लिखें और पढ़ें

Lesson 4 of 12 · about 12 minutes · echo, > to write, >> to add a line, cat to read.

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Step 1 of 2

echo, > and >>

echo "hello" prints text. Add an arrow and the text goes into a file instead:

echo "Masala chai ₹10" > menu.txt — one arrow writes: it creates the file, or wipes it and starts fresh.
echo "Ginger chai ₹15" >> menu.txt — two arrows add: a new line at the end, keeping what was there.
cat menu.txt shows what is inside a file.

Careful: a single > on an existing file throws away its old text. When in doubt, use >>.

Example

echo "Poha ₹20" > tiffin.txt
echo "Upma ₹25" >> tiffin.txt
cat tiffin.txt

In your home folder, create menu.txt with exactly two lines:

Write the first line with >, add the second with >>, then show the file with cat menu.txt.

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terminalCtrl ⏎

A safe practice terminal. Type a command and press Enter. Type help to list commands. Tab completes names, ↑ recalls the last command.

asha@indiadigital:~$

Files · ~ = /home/asha

Your home folder is empty.

Git timeline

No git repository yet. Start with git init.

Checklist

Press Run to check your code.

Lesson notes (text version)

echo "hello" prints text. Add an arrow and the text goes into a file instead:

echo "Masala chai ₹10" > menu.txt — one arrow writes: it creates the file, or wipes it and starts fresh.
echo "Ginger chai ₹15" >> menu.txt — two arrows add: a new line at the end, keeping what was there.
cat menu.txt shows what is inside a file.

Careful: a single > on an existing file throws away its old text. When in doubt, use >>.

                echo "Poha ₹20" > tiffin.txt
echo "Upma ₹25" >> tiffin.txt
cat tiffin.txt

In your home folder, create menu.txt with exactly two lines:

Write the first line with >, add the second with >>, then show the file with cat menu.txt.

Sometimes wiping a file is what you want — like changing yesterday's notice board. One > replaces everything; then >> adds more lines below.

Real developers use this all the time to create small config and note files straight from the terminal.

notice.txt still says "Closed today". Make it contain exactly these two lines:

The old text must be gone. Check with cat notice.txt.