LinuxQuestions.org - [SOLVED] Delete specific newlines on a file.

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Tchiarot

07-11-2014 05:13 PM

Delete specific newlines on a file.

Hi Friends,

I have a procedure for delete some specific newline on a file.
For example with the file ex01:

Code:

Chiarot:teddy$cat ex01

Pencil1,101,102,103

Desktop2,201,104,106

nil,202,203,204,205,206,207

nilB,208,209,210,211,150,151,152,153,154,155,156

nilC,208,209,210,211,150,151,152,153,154,155,156

nilD,208,209,210,211,150,151,152,153,154,155,156

I should obtain:

Code:

 sed

Chiarot:tmp$cat ex01

Pencil1,101,102,103

Desktop2,201,104,106

nil1,202,203,204,205,206,207,208,209,210,211,150,151,152,153,154,155,156

Now I using a sed and grep:

Code:

Chiarot:teddy$cat pr.sh

#!/bin/bash

egrep -v "nil" /tmp/ex01 > /tmp/ex01A

egrep -R "nil" /tmp/ex01 | sed -e ':a;N;$!ba;s/\n//g' -e 's/nil[B|C|D]//g' > /tmp/ex01B

cat /tmp/ex01A /tmp/ex01B > /tmp/ex01Final

rm /tmp/ex01A; rm /tmp/ex01B

It works.. but I'm trying to use the sed for made the change only in the file and be more efficient with temp files.

Some ideas to reduce this code?.

coralfang

07-11-2014 06:15 PM

You could store the temporary parts in variables, something like this:

Code:

#!/bin/bash

TMPVAR1=$(egrep -v "nil" /tmp/ex01)

TMPVAR2=$(egrep -R "nil" /tmp/ex01 | sed -e ':a;N;$!ba;s/\n//g' -e 's/nil[B|C|D]//g')

echo -e "$TMPVAR1\n$TMPVAR2" > /tmp/ex01Final

EDIT:
or even better..

Code:

#!/bin/bash

echo -e "$(egrep -v 'nil' /tmp/ex01)\n$(egrep -R 'nil' /tmp/ex01 | sed -e ':a;N;$!ba;s/\n//g' -e 's/nil[B|C|D]//g')" > /tmp/ex01Final

Tchiarot

07-11-2014 06:27 PM

That's a good idea, thanks coralfang.

It works very well, but there is no way to use only sed for replace nilB, nilC and nilD for nothing and paste this lines only with sed into the file?.
It could work even better than now.

Tchiarot

07-11-2014 07:06 PM

Finally find a even better solution:

Code:

sed -e '/^nil/{:a;N;$!ba;s/\n//g}' -e 's/nil[B|C|D]//g' /tmp/ex01 > /tmp/ex01Final

Can I execute it in the same file?, whithout use redirect?

Tchiarot

07-11-2014 07:18 PM

This is the final expression:

Code:

sed -i '/^nil/{:a;N;$!ba;s/\n//g;s/nil[B|C|D]//g}' /tmp/ex01

or:

Code:

sed -e '/^nil/{:a;N;$!ba;s/\n//g;s/nil[B|C|D]//g}' /tmp/ex01 > /tmp/ex01Final

Thx a lot for help.

danielbmartin

07-13-2014 07:47 PM

With this InFile ...

Code:

Chiarot:teddy$cat ex01

Pencil1,101,102,103

Desktop2,201,104,106

nil,202,203,204,205,206,207

nilB,208,209,210,211,150,151,152,153,154,155,156

nilC,208,209,210,211,150,151,152,153,154,155,156

nilD,208,209,210,211,150,151,152,153,154,155,156

... this awk ...

Code:

awk -F, '{if (substr($0,1,3)!="nil") print

  else for (j=2;j<=NF;j++) if (!index(ns,$j)) ns=ns","$j}

  END{print "NIL1" ns}' $InFile >$OutFile

... produced this OutFile ...

Code:

Chiarot:teddy$cat ex01

Pencil1,101,102,103

Desktop2,201,104,106

NIL1,202,203,204,205,206,207,208,209,210,211,150,151,152,153,154,155,156

Daniel B. Martin

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