sed

Sed commands

• d : delete text.
• p : print text.
• s : search and replace txt.

Sed options

• -e : when use many commands.
• -f : load the commands in the script-file.
• -n : silent mode.

Example

1. Print lines containing a pattern:

    $ sed -n '/erors/p' example`
   

2. Deleting lines of input containing a pattern

    $ sed 'erors/d' example
   

3. The meta-characters mean either starting and ending

    # ^ is staring and $ is ending.
    $ sed -n '/^This.*errors.$/p' example
   

4. Ranges of lines

    $ sed -n '2,4p' example
    $ sed '3,$d' example
    # $ sed -n '/(From the line pattern matches)/,/(To the line pattern matches)/p' example
    $ sed -n '/a text/,This/p' example
    It is a text with erors.
    Lots of erors.
    So much erors, all these erors are making me sick.
    This is a line not containing any errors.
   

5. Find and replace

    $ sed 's/erors/errors/g' example
   

MISC.

1. Use the temporary file in script:

    TEMPFILE="/var/tmp/sed.$PID.tmp"
    # $PID, $$ or $BASHPID
   

Reference

• https://www.tldp.org/LDP/Bash-Beginners-Guide/html/chap_05.html