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    30 examples of the sed command - with regex

    Sed is a non-interactive text editor. It comes from English [S]tream [ED]itor, ie text flow editor. GNU Sed is currently used by most Linux distributions and has the most new features: GNU/Linux.

    It’s case sensitive

    • -i change the file
    • -e print to screen without changing file
    • -n suppress, show only command output
    • s replaces one piece of text with another
    • ! inverts the logic of the command
    • ; command separator
    • | string separator
    • d at the end delete
    • p at the end prints
    • g at ​​the end (as d and p is used) changes all occurrences
    • q quit sed, does not continue command

    Complete list of GNU sed character classes

    • [[: alnum:]] Alphabetic and Numeric [a-z A-Z 0-9]
    • [[: alpha:]] Alphabetic [a-z A-Z]
    • [[: blank:]] Blank character, space, or tab [\ t]
    • [[: cntrl:]] Control characters [\ x00- \ x1F \ x7F]
    • [[: digit:]] Numbers [0-9]
    • [[: graph:]] Any visible character (i.e. except blank) [\ x20- \ x7E]
    • [[: lower:]] Lowercase letters [a-z]
    • [[: upper:]] Capital letters [A-Z]
    • [[: print:]] Visible characters (ie except control characters) [\ x20- \ x7E]
    • [[: punct:]] Score [-! ”# $% & ‘() * +,. /:;? @ [] _` {} ~].
    • [[: space:]] White space [\ t \ r \ n \ v \ f]
    • [[: xdigit:]] Hexadecimal Number [0-9 a-f A-F]

    1 - Swap all words in one file for another

    sed -i 's/word/other/' file.txt

    2 - Prints only the ninth line

    sed -n '9p' file.txt

    3 - Prints from the sixth line to the ninth line

    sed -n '6.9p' file.txt

    4 - Delete all lines containing the word string in the file.

    sed -i '/dmx/d' file.txt

    5 - Put one word at the beginning of each line.

    sed 's/^/word/' file.txt

    6 - Put a word at the end of each line.

    sed 's/$/word/' file.txt

    7 - Prints only lines that START with the string ‘http’

    sed -n '/^http/p' file.txt

    8 - Deletes only lines that START with the string ‘http’

    sed -n '/^http/d' file.txt

    9 - Exchange ALL occurrences of the word “marcos”, “eric”, “camila” with the word “penguin”

    sed 's/marcos\|eric\|camila/penguin/g' file.txt

    10 - Exchange everything between the words “Marcos” and “Eric” for the word “they”, for example, the text is:

    “On Saturday Marcos went out to bike with Eric, but they didn’t stay up late.” And it will look like this: “On Saturday they didn’t stay up late.”

    sed's/Marcos.*Eric/they/' file.txt

    11 - Delete blank line and change file

    sed -i '/^$/d' file.txt

    12 - Replaces “foo” with “bar” only lines containing “plop”

    sed '/plop/s/foo/bar/g' file.txt

    13 - Replaces “foo” with “bar” except lines containing “plop”

    sed '/plop/!s/foo/bar/g 'file.txt

    14 - Insert Line 2 with line 7 the “#” at the beginning of each line

    sed '2,7s/^/#/' file.txt

    15 - Inserts the word ‘NEW’ at the beginning of each line from line 21 to line 28

    sed -i '21,28s/^/NEW/' file.txt

    16 - Swap everything between the tags “<” and “>” for the word “CODE”:

    sed 's/<[^>]*>/CODE/g' file.txt

    17 - Prints only first occurrence of line with given string

    sed -n '/day/{p;q;}' file.txt

    18 - Include text at end of line 9

    sed '9s/$/end of line/' file.txt

    19 - Put all lines into one

    sed ':a;$!N;s/\n//;ta;' file.txt

    20 - Replaces the word “BEAUTY” with “YES” only between certain lines.

    sed '3,6s/BEAUTY/YES/' file.txt

    21 - Deletes what is between the word “spoke” and “second” (delimiters)

    sed '/second/{/spoke/{s/second.*spoke//;t};:a;/spoke/!{N;s/\n//;ta;};s/second.*spoke/\n/;}' file.txt

    22 - Removes HTML commands

    sed 's/<[^>]*>//g' file.txt

    23 - Deletes the 1st character of the sentence.

    sed 's/.//' file.txt

    24 - Deletes the 4th character of the sentence.

    sed 's/.//4' file.txt

    25 - Deletes the first 4 characters

    sed 's/.\{4\}//' file.txt

    26 - Deletes at least 4 characters

    sed 's/.\{4,\}//' file.txt

    27 - Deletes 2 to 4 characters

    sed 's/.\{2,4\}//' file.txt

    28 - Range Examples

    echo "aáeéiíoóuú" | sed "s/[a-u]//g"
áéíóú
    echo "aáeéiíoóuú" | sed "s/[á-ú]//g"
aeiou

    29 - Transforms text (URL) into HTML link tags.

    It was: http://www.com

    It is: <a href="http://www.com">http://www.com</a>

    sed 's_\<\(ht\|f\)tp://[^ ]*_<a href="&">&</a>_' file.txt

    30 - Regular Expressions with SED (sed regex)

    This sed reads data from file.txt and erases (command d) from the first line to the line containing 3 numbers in a row, throwing the result on the screen. If you want to save the result, redirect it to another file, not the file.txt itself.

    sed '1,/[0-9]\{3\}/d' file.txt

    Delete numbers

    s/[0-9]\+//g' file.txt

    Prints only lines containing SCORE

    sed -n '/[[:punct:]]/p' file.txt

    Print only lines beginning with Numbers

    sed -n '/^[[:digit:]]/p' file.txt

    Formatting Phone Number

    We have a file with the phone numbers like this:

    7184325689
4333285236
1140014004
3633554488

    Running some of these command modes in SED:

    • Neanderthal Mode

    Replaces 2 characters “..” with “&” which is the output of the request. Performs another sed to replace 8 characters again with “&” Note: You must always escape the parentheses “(“ and “)”

    sed 's/../\(&\)/' file.txt | sed 's/......../&-/' file.txt
    • Medieval mode

    Same as above, just put the “{8}” to mark 8 characters “.” Also, ALWAYS need to escape the “{“ and “}” keys

    sed 's/../\(&\)/' file.txt | sed 's/.\{8\}/&-/' file.txt
    • Modern mode

    Instead of throwing the exit, I separated the command with a semicolon “;” and launched another sed “s”

    sed 's/../\(&\)/;s/.\{8\}/&-/' arquivo.txt
    • Postmodern mode

    This mode is to understand the following

    The first command in parentheses “(..)” Then separated by slash
    I threw or command in parentheses “\ (.{4 } )” The first command output goes to bar 1 “\1” And the second command for slash 2 “\2” It could also have bar 3, n,…

    sed 's/\(..\)\(.\{4\}\)/(\1)\2-/g' arquivo.txt

    Stays like this:

    (71) 8432-5689
(43) 3328-5236
(11) 4001-4004
(36) 3355-4488

    Thanks for read.

    sed linux terminal gnu

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