Tutorial Lengkap Sed untuk Text Processing di Linux

Update: 3 February 2026

Baca: 4 menit

Tutorial Lengkap Sed untuk Text Processing di Linux

Sed (Stream Editor) adalah text processing utility yang powerful untuk melakukan basic transformations pada input stream. Meski tidak se-powerful AWK untuk complex processing, Sed unggul dalam text substitution dan manipulation.

1. Sintaks Dasar Sed

Struktur Command

sed [options] 'command' file
sed [options] -e 'command1' -e 'command2' file

Command Fundamental

# Print semua baris (default behavior)
sed '' file.txt
sed -n 'p' file.txt

# Print baris tertentu
sed -n '5p' file.txt        # Line 5
sed -n '5,10p' file.txt     # Lines 5-10
sed -n '$p' file.txt        # Last line
sed -n '1~2p' file.txt      # Every 2nd line starting from 1

# Print multiple ranges
sed -n '1p;5p;10p' file.txt

2. Substitution dengan Sed

Basic Substitution

# Replace text (hanya first occurrence per line)
sed 's/old/new/' file.txt

# Replace all occurrences dalam line (global)
sed 's/old/new/g' file.txt

# Replace specific occurrence
sed 's/old/new/2' file.txt    # Replace 2nd occurrence
sed 's/old/new/2g' file.txt   # Replace 2nd dan seterusnya

# Use different delimiters (useful untuk paths)
sed 's|/usr/local|/opt|g' file.txt
sed 's#/home/user#/data#g' file.txt
sed 's_old_new_g' file.txt

Advanced Substitution

# Case insensitive
sed 's/old/new/gi' file.txt

# Only print modified lines
sed -n 's/old/new/gp' file.txt

# Capture groups dengan backreferences
sed 's/\(.*\):\(.*\)/\2: \1/' file.txt

# Replace dengan line number
sed = file.txt | sed 'N; s/\n/ /'

# Replace dengan environment variable
sed "s/USER/$USER/g" file.txt

# Replace only specific lines
sed '5s/old/new/' file.txt      # Line 5 only
sed '/pattern/s/old/new/' file.txt  # Lines matching pattern
sed '1,10s/old/new/' file.txt   # Lines 1-10

3. Deletion dan Insertion

Deleting Lines

# Delete baris tertentu
sed '5d' file.txt             # Delete line 5
sed '5,10d' file.txt          # Delete lines 5-10
sed '$d' file.txt             # Delete last line
sed '1d' file.txt             # Delete first line

# Delete based on pattern
sed '/pattern/d' file.txt     # Delete lines with pattern
sed '/pattern/!d' file.txt    # Delete lines NOT matching pattern

# Delete blank lines
sed '/^$/d' file.txt
sed '/^[[:space:]]*$/d' file.txt

# Delete lines dengan whitespace only
sed '/^[[:space:]]*$/d' file.txt

Inserting dan Appending

# Insert before line
sed '5i\This is new line' file.txt

# Append after line
sed '5a\This is appended' file.txt

# Insert multiple lines
sed '5i\
Line 1\
Line 2\
Line 3' file.txt

# Append after last line
sed '$a\This is last' file.txt

# Insert at beginning of file
sed '1i\# Header' file.txt

4. Addressing dan Ranges

Line Addressing

# Single line
sed '5s/old/new/' file.txt

# Line range
sed '5,10s/old/new/' file.txt

# From line to end
sed '5,$s/old/new/' file.txt

# Pattern matching
sed '/start/,/end/s/old/new/' file.txt

# Regex pattern
sed '/^#/s/old/new/' file.txt

# Multiple addresses
sed -e '1s/^/START/' -e '$s/$/END/' file.txt

Range Operations

# Process range
sed -n '/START/,/END/p' file.txt

# Delete range
sed '/START/,/END/d' file.txt

# Substitute dalam range
sed '/START/,/END/s/foo/bar/' file.txt

5. Advanced Sed Techniques

Multiple Commands

# Multiple sed commands
sed -e 's/foo/bar/' -e 's/baz/qux/' file.txt

# Command file
sed -f commands.sed file.txt

# Commands dalam file commands.sed:
# s/foo/bar/
# s/baz/qux/
# 5d

In-place Editing

# Edit file in-place (backup original)
sed -i.bak 's/foo/bar/g' file.txt

# Edit file in-place tanpa backup
sed -i 's/foo/bar/g' file.txt

# Edit multiple files
sed -i 's/foo/bar/g' *.txt

Working dengan Multiple Lines

# Print next line juga
sed -n '/pattern/{N;p}' file.txt

# Join lines
sed ':a;N;$!ba;s/\n/ /g' file.txt

# Delete newlines
sed ':a;N;$!ba;s/\n//g' file.txt

# Merge every 2 lines
sed 'N;s/\n/ /' file.txt

# Swap line order
sed 'n;G;h;P;d' file.txt

Case Conversion

# Convert ke uppercase
sed 's/.*/\U&/' file.txt

# Convert ke lowercase
sed 's/.*/\L&/' file.txt

# Capitalize first letter
sed 's/.*/\u&/' file.txt

# Title case (setiap word)
sed 's/\b\([a-z]\)/\u\1/g' file.txt

6. Praktis One-Liners

File Manipulation

# Remove comments dan blank lines
sed '/^[[:space:]]*#/d; /^[[:space:]]*$/d' config.conf

# Add line numbers
sed = file.txt | sed 'N; s/\n/ /'

# Double space file
sed G file.txt

# Reverse lines of file
sed '1!G;h;$!d' file.txt

# Remove trailing whitespace
sed 's/[[:space:]]*$//' file.txt

# Remove leading whitespace
sed 's/^[[:space:]]*//' file.txt

# Remove both leading dan trailing
sed 's/^[[:space:]]*//;s/[[:space:]]*$//' file.txt

# Indent each line dengan 4 spaces
sed 's/^/    /' file.txt

Data Processing

# Convert spaces ke tabs
sed 's/  */	/g' file.txt

# Convert tabs ke spaces
sed 's/	/    /g' file.txt

# Remove ANSI color codes
sed 's/\x1B\[[0-9;]*[JKmsu]//g' file.txt

# URL encode
sed 's/ /%20/g' file.txt

# Wrap long lines at 80 characters
sed -n -e ':a' -e 's/^\(.\{80\}\)/\1\\/;ta' -e 'p' file.txt

Configuration File Editing

# Uncomment line
sed -i 's/^#Port 22/Port 22/' /etc/ssh/sshd_config

# Change value
sed -i 's/^Port 22/Port 2222/' /etc/ssh/sshd_config

# Add setting if not exists
sed -i '/^#*Port 22/!a\Port 2222' /etc/ssh/sshd_config

# Delete setting
sed -i '/^PermitRootLogin yes/d' /etc/ssh/sshd_config

# Replace dalam tag HTML
sed 's/<[^>]*>//g' file.html

Kesimpulan

Sed adalah tools yang sangat powerful untuk text transformation. Meski learning curve sedikit curam, menguasai Sed akan menghemat banyak waktu dalam text processing tasks.

Kapan Menggunakan Sed vs AWK:

Sed: Simple text substitution, deletion, insertion
AWK: Field-based processing, calculations, complex logic
Both: Often used together dalam pipelines

Tips:

Selalu test dengan -n dan p sebelum in-place editing
Gunakan backup (-i.bak) untuk file penting
Kombinasikan dengan pipes untuk workflow complex
Gunakan command files untuk scripts panjang

Alternatives:

tr: Simple character translation
cut: Field extraction sederhana
perl -pe: Perl one-liners (more powerful)
awk: Field-based processing