Sed Commands for Penetration Testing

Common sed commands for editing and reformatting text during pentests.

Sed is a stream editor that lets you search, replace, and reformat text without opening a file in an editor. It’s especially handy for cleaning up wordlists and extracted data during an engagement.

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sed -n '2345p' flag19   # Print only line 2345 of a file (awk 'NR==2345' flag19 works too)

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sed 's/,/\n/g' comma_separated.txt > one_per_line.txt   # Put each comma-separated value on its own line

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sed ':a;N;$!ba;s/\n/", "/g' subdomains.txt | sed 's/^/"/;s/$/"/'   # Join every line into one comma-separated, quoted string

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sed 's/\./\n/g' subdomains.txt > words.txt   # Split text at every . and put each part on its own line

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wget -q -O - https://example.com/docs | sed -n 's/.*<h4[^>]*>\(.*\)<\/h4>.*/\1/p'   # Extract the text inside every <h4> tag from a downloaded page

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find . -type f -exec sed -i 's/.*://' {} \;   # Strip everything before the first colon on every line, in every file in the current tree

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sed 's/[^[:print:]]//g' wordlist.txt | grep -E '^.{8}$'   # Strip non-printable characters, then keep only 8-character words