CODEWITHSUNDEEP
awksed
user2854333
user2854333

Reputation: 640

Delete everything before and after a string using sed

I have data in a file in below form :--

The symbol ":=" was substituted for "QUERY" to continue.

SQL> _id                              : MS
itm                         : 4
it                          : NO

------

PL/SQL procedure successfully completed.

I want to delete everything before _id and after ------ .

To delete everything before _id I used following sed 

sed '/_id/,$!d' 1.txt

It deletes the row before _id but doesnt delete SQL> .

Similarly I used below sed to delete all everything after ------ but it doesnt delete the rows below it 

sed 's/\------.*/------/' 1.txt

Can someone help me where I am doing wrong ? What I need is :--

_id                         : MS
itm                         : 4
it                          : NO

Upvotes: 1

Views: 836

Answers (1)

John1024
John1024

Reputation: 113814

Using sed

Try:

$ sed -n '/_id/,/------/{ s/.*_id/_id/; /------/q; p}' 1.txt
_id                              : MS
itm                         : 4
it                          : NO

How it works:

  • -n

    This tells sed not to print unless we explicitly ask it to.

  • /_id/,/------/{...}

    This selects a range of lines that start with a line containing _id and end with a line containing ------. For those lines the commands in curly braces are executed.

  • s/.*_id/_id/

    On the line that contains _id, this removes everything before _id.

  • /------/q

    On the line that contains ------, this tells sed to quit.

  • p

    For lines that reach this command, this tells sed to print the line.

Using awk

$ awk -v RS='------' '/_id/{sub(/.*_id/, "_id"); print}' ORS="" 1.txt
_id                              : MS
itm                         : 4
it                          : NO

How it works:

  • -v RS='------'

    This set ------ as the record separator.

  • /_id/{sub(/.*_id/, "_id"); print}

    For any records that contain _id, we remove everything before _id and print the current record.

  • ORS=""

    This sets the output record separator to the empty string.

Upvotes: 2

Related Questions