unix command

[mango_1]

hello all! I'd like to ask if there's a unix command that could delete parts of the file given a string. Example:
Given: File1 which contains
--testing--
test123
--testing--
--hello--
world
--hello--

If my string is hello, the output would be another file or the same file but without the hello block. So, the output would be
--testing--
test123
--testing--

if anybody knows please help! thanks!

[Patrick Wallek]

The simplest, least elegant way would be:

# grep -v hello somefile > some_other_file

The above would look for all occurences of hello anywhere in a line in the file somefile and put all lines EXCEPT those in the file some_other_file.

I'm sure others will give you examples with Perl, awk, sed, etc. as there are lots of ways to do this.

[curt larson_1]

lets see

cat file | sed '/^--hello--/d' > newFile

cat file | awk '{if ( $0 !~ "--hello--" ) print $0;}' > newFile

[Caesar_3]

Hello!

Use perl, read the file and write to the
new one all what you want from the file.

Caesar

[curt larson_1]

and

ex -s +"1,$ /^--hello--/ d|w!q" file1

[Hai Nguyen_1]

Try this which will make a NEW File1:

# cat File1 | grep -v "--hello--" | tee File1 >/dev/null

Hai

[James R. Ferguson]

Hi:

# sed -n '/--hello--/,/--hello--/!p' filename > filename.new

Regards!

...JRF...

[Pete Randall]

Do a search of the forums, using the "exact phrase" option, for "handy one liners for sed". I don't have the document available to me at the moment but I think it will provide what you seek.


Pete

[mango_1]

hello all! thanks for the info! what if there is additional text after hello. let's say.
--testing--
test123
--testing--
--hello--
hiya
--hello--
--world--
earth
--world--

is there a way to delete everything starting from hello to world. so the end output will be
--testing--
test123
--testing--

but without hard coding it. because I might not know what's the next block after hello. thanks so much! I'm relatively new with this.

[curt larson_1]

can you provide a definition for what a "block" of output is. or a relationship between hello and world that is going to be deleted.

[James R. Ferguson]

Hi (again):

For your last question, examine the input you have. Now, you want only the block bounded, inclusively by "---testing--" and "---testing---". This is similar to the first solutipm I offered, but without negating (with the '!' flag)the 'p'rint:

# sed -n '/--testing/,/--testing/p' filein > fileout

This says, "dont print (output) anything, except, (p)rint that which begins (and ends) with the regular expression /--testing/.

Regards!

...JRF...

[Fragon]

Hi,
Do you mean from the first "hello" to last "world", all lines be deleted?

-ux

[mango_1]

hi thanks for the help everyone.

curt: a block is those lines enclosing the
--xxxxxx---
hello
world
--xxxxxx---

james: thanks for the help. I have another question to that. what if the file contains
--abc--
def
--abc--
--testing--
123
--testing--
--hello--
world
--hello--
--mango--
fruit
--mango--

then output the following
--abc--
def
--abc--
--testing--
123
--testing--
where you only know testing string and not the abc. could i use sed -n ...1,/--testing--/. hmmm...

thanks again everyone.

[mango_1]

hpux: I meant from the whole block of hello
just
--hello--
world
--hello--

[mango_1]

hi james! one last question please. what can I do to not include the --testing-- headers for example

I have this file format:
--abc--
def
--testing--
123
--hello--
world

then

sed -n '1,/--testing--/p' file19 > file23

will print out
--abc--
def
--testing--

is there a way to remove the --testing-- being printed out to the new file? eg
--abc--
def

or should I just reformat my file. hmmm

is there a way to manipulate the same file? in this case file19 without having to redirect the output to another file? just wondering. thanks!

[James R. Ferguson]

Hi (again):

In answer to your question about using:

# sed -n '1,/--testing--/p' filein > fileout

...that is legitimate syntax for "from record #1 through (inclusive) a record with the regular expression /--testing--/ print the output. Using your file, though as posted, you would get only this:

--abc--
def
--abc--
--testing--

If you want to extract the "blocks" /--abc--/ *and* /--testing--/ I suggest you do something like this:

# sed -n '/--abc--/,/--abc--/p' filein > fileout

# sed -n '/--testing--/,/--testing--/p' filein >> fileout

...that is, make two passes with the same input file, *appending* the second pass to the output of the first.

Regards!

...JRF...

[James R. Ferguson · Accepted solution]

Hi Mango:

With regard to your last question..."to not include the --testing-- headers", here's one approach:

# V=--testing---
# sed -n "/${V}/,/${V}/p" filein|grep -v \\${V}

Note carefully the two backslashes before the ${V} variable in the 'grep' pipeline. Without these, 'grep' will not interpret the "--testing--" expression correctly.

Regards!

...JRF...

[mango_1]

thanks james! that really solved my problem. :) Is there a way to manipulate the same file. I don't know if its going to be inefficient to create another file when I'm just editing the same file. thanks!

[mango_1]

is this possible

test="==testin=="
sed -n "1,/==$test==/p" file | grep -v \\$test > file

thanks

[James R. Ferguson]

Hi Mango:

I think you wanted to write:

# test="==testin=="
# sed -n "1,/$test/p" file|grep -v \\$test > file

That is, from record-1 through a record with the string ==testin== ...

...and the answer is *NO* you can't. You need to use an intermediate file. In the above, you will end up with an empry file. You cannot edit inplace nor can you read and write to the same file (which is what the above pipeline does!

Regards!

...JRF...