Remove (Delete) Duplicate Email Addresses in Text Files — 5 Simple Ways

Remove (Delete) Duplicate Email Addresses in Text Files — 5 Simple Ways

1) Use sort + uniq (Linux/macOS)

• Command: sort emails.txt | uniq > deduped.txt
• Preserves one instance of each exact line. Use sort -u to combine steps.
• To keep original order, use awk/perl methods below.

2) awk to preserve first occurrence order

• Command: awk ‘!seen[$0]++’ emails.txt > deduped.txt
• Keeps the first appearance of each exact line and removes later duplicates.

3) Python script for flexible parsing

• Example (handles emails within larger text and normalizes case):

Code
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import re with open(‘emails.txt’) as f:text = f.read() emails = re.findall(r’[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+.[A-Za-z]{2,}‘, text) seen, out = set(), [] for e in emails:

 
k = e.lower() if k not in seen:     seen.add(k)     out.append(e) 
with open(‘deduped.txt’,‘w’) as f:
f.write(" 
”.join(out)) 

4) PowerShell (Windows)

Command: Get-Content emails.txt | Sort-Object -Unique | Set-Content deduped.txt
To preserve first occurrence order:

Code
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\(seen = @{} </span>Get-Content emails.txt | ForEach-Object {   if (-not \)seen.ContainsKey(\(_)) { \)seen[\(_] = \)true; $_ } } | Set-Content deduped.txt 
5) Text editors / spreadsheet tools

Use editors with regex find/replace (e.g., VS Code) or import into Excel/Sheets and use “Remove duplicates”.
Good for small files and visual review; prone to manual error on large files.

Tips & considerations

Normalization: lowercase emails, trim whitespace, remove surrounding punctuation before deduping.
Email parsing: use robust regex or libraries for complex text; avoid naive patterns that capture invalid strings.
Large files: use streaming approaches (awk, Python iterator, or external tools) to avoid high memory use.
Back up original file before changes.
If you need a ready-to-run script for your platform or want handling for emails embedded in paragraphs, tell me your OS and file sample.