lab21.md

LAB 21: Operasi Fail

Prerequisites

• Selesai Lab 20

Bahagian 0: Connect ke EC2 Instance

Langkah 1: Connect Menggunakan Session Manager

1. Pergi ke EC2 Console
2. Select instance anda
3. Click Connect > Session Manager > Connect
4. Switch to bash: bash

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Bahagian 1: Command touch

Langkah 1: Fahami touch

touch - Cipta fail atau update timestamp fail

cd /var/www/site1/html

ls -l index.html

sudo touch index.html

ls -l index.html

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Bahagian 2: Command echo (Perintah output)

Langkah 1: Fahami echo

echo - output konten kepada terminal

echo "Hello DevOps"

Langkah 2: Kombinasi dengan Redirector

Redirector > - Tulis konten dalam fail

cd ~
echo "This is line 1" > test.txt

cat test.txt

echo "This is NEW line 1" > test.txt

cat test.txt

Nota: > akan buang konten lama dan tulis konten baru.

Langkah 3: Redirector >> (Tambah)

Redirector >> - Tambah konten kepada file

echo "This is line 2" >> test.txt
echo "This is line 3" >> test.txt

cat test.txt

Nota: >> akan tambah konten baru tanpa buang konten sebelumnya.

Langkah 4: Buat fail colors.txt dengan echo & redirector

cd ~
echo "red" >> colors.txt
echo "green" >> colors.txt
echo "blue" >> colors.txt

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Bahagian 3: Command cat (Perintah lihat teks)

Langkah 1: Lihat kontent fail

cat - concatenate konten

cat colors.txt

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Bahagian 4: grep (Perintah carian teks)

Langkah 1: Fahami grep

grep - Cari teks dalam fail

grep "red" colors.txt

grep "blue" colors.txt

Langkah 2: Cari dalam fail html

grep "Version" /var/www/site1/html/index.html

-i - case-insensitive

cat /var/www/site1/html/index.html | grep -i "version"

grep "title" /var/www/site1/html/index.html

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Bahagian 5: Pipe | (Menghubungkan perintah)

Langkah 1: Fahami Pipe

Pipe | - Send output dari satu command ke command lain

cat colors.txt | grep "red"

Nota: | ambil output dari command kiri, hantar ke command kanan.

Langkah 2: cat dengan grep

# View file and search
cat /var/www/site1/html/index.html | grep "Version"

Langkah 3: Practical Examples

# Test website and check version
curl localhost | grep "Version"

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Bahagian 6: Command tee (Perintah input & output)

Langkah 1: Fahami tee

tee - Tulis konten ke dalam fail dan tunjukkan serta merta di terminal

echo "Test with redirector" > redirect.txt
cat redirect.txt

echo "Test with tee" | tee tee.txt

Nota: tee berguna bila nak save output DAN tengok sekali.

Langkah 2: Guna tee jika perlu sudo

cd /var/www/site1/html

# akan gagal
sudo echo "test" > test-fail.txt

# akan lulus
echo "test" | sudo tee test-success.txt > /dev/null

# Verify
ls -l test-success.txt

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Bahagian 7: Command cp (Perintah salin fail)

Langkah 1: Fahami cp

cp - Menyalin fail menjadi fail berbeza

cd /var/www/site1/html

sudo cp index.html index-backup.html

ls -l index*

Langkah 2: Salin fail dengan menggunakan date

sudo cp index.html index-$(date +%Y%m%d).html

ls -l

Langkah 3: Salin fail kepada folder berbeza

sudo mkdir -p /var/www/backups

sudo cp index.html /var/www/backups/

ls -l /var/www/backups/

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Bahagian 8: Command mv (Perintah alih)

Langkah 1: Fahami mv

mv - Mengalihkan file kepada nama baru

sudo touch old-name.html

sudo mv old-name.html new-name.html

ls -l *name*.html

Langkah 2: Mengalihkan fail ke tempat baru

sudo mkdir -p archive

sudo mv index-backup.html archive/

ls -l archive/

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Bahagian 9: Command find (Perintah cari fail atau directory)

Langkah 1: Fahami find

find - cari fail

cd /var/www/site1/html

find . -name "index.html"

find . -name "*.html"

Langkah 2: Cari file dan directory

find /var/www/site1/html -type f

find /var/www -type d

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Command Summary

Redirectors & Pipes

Symbol	Nama	Fungsi	Contoh
>	Redirect (overwrite)	Write to file, replace old content	echo "text" > file.txt
>>	Redirect (append)	Add to file, keep old content	echo "text" >> file.txt
|	Pipe	Send output to next command	cat file | grep "word"

File Creation

Command	Fungsi	Contoh
touch file	Create empty file or update timestamp	touch test.txt
echo "text" > file	Create file with text	echo "hello" > test.txt
echo "text" >> file	Update file with text	echo "hello 2" >> test.txt
tee file	Write and display	echo "text" | tee file.txt

File Viewing

Command	Fungsi	Contoh
cat file	Display file content	cat index.html
cat file | grep	Search in file	cat index.html | grep Version

File Operations

Command	Fungsi	Contoh
cp file backup	Copy file	cp index.html backup.html
mv old new	Rename file	mv old.html new.html
mv file dir/	Move file	mv file.txt backup/

Search Commands

Command	Fungsi	Contoh
grep "text" file	Search text in file	grep "Version" index.html
find . -name "file"	Find file by name	find . -name "*.html"
find . -type f	Find files only	find /var/www -type f

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