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sed

Introduction​

This cheat sheet provides a quick reference for some common sed (stream editor) commands and concepts. sed is a powerful text manipulation tool in Unix-like operating systems.

sed Concepts​

Basic sed Usage​

sed is used to perform text transformations on input text (a file or input stream) using a set of commands.

  • Replace text in a file and print the result:

    sed 's/old-text/new-text/' file.txt

  • Replace text in a file and save the changes in-place:

    sed -i 's/old-text/new-text/' file.txt

  • Replace text globally (all occurrences):

    sed 's/old-text/new-text/g' file.txt

Regular Expressions​

sed uses regular expressions for pattern matching and manipulation.

  • Use a regular expression as a pattern:

    sed '/pattern/s/old-text/new-text/' file.txt

  • Match lines that start with a pattern:

    sed '/^start/s/old-text/new-text/' file.txt

  • Match lines that end with a pattern:

    sed '/end$/s/old-text/new-text/' file.txt

Addressing Lines​

You can specify line addresses to target specific lines in a file.

  • Apply the s command to lines 1 to 5:

    sed '1,5 s/old-text/new-text/' file.txt

  • Apply the s command to lines matching a pattern:

    sed '/pattern/ s/old-text/new-text/' file.txt

Reading from Files​

sed can read commands from a file.

  • Read sed commands from a file and apply them: 
    sed -f script.sed input.txt

Deleting Lines​

sed can delete lines from a file.

  • Delete lines matching a pattern:

    sed '/pattern/d' file.txt

  • Delete lines between two patterns (inclusive):

    sed '/start/,/end/d' file.txt

sed Command-Line​

  • Replace text in a file and print the result:

    sed 's/old-text/new-text/' file.txt

  • Replace text in a file and save the changes in-place:

    sed -i 's/old-text/new-text/' file.txt

  • Replace text globally (all occurrences):

    sed 's/old-text/new-text/g' file.txt

  • Use a regular expression as a pattern:

    sed '/pattern/s/old-text/new-text/' file.txt

  • Match lines that start with a pattern:

    sed '/^start/s/old-text/new-text/' file.txt

  • Apply the s command to lines 1 to 5:

    sed '1,5 s/old-text/new-text/' file.txt

  • Read sed commands from a file and apply them:

    sed -f script.sed input.txt

  • Delete lines matching a pattern:

    sed '/pattern/d' file.txt

  • Delete lines between two patterns (inclusive):

    sed '/start/,/end/d' file.txt

Conclusion​

This cheat sheet covers some common sed (stream editor) commands and concepts. sed is a versatile text manipulation tool, making it essential for text processing and editing tasks; refer to the GNU sed documentation for more in-depth information and advanced usage.