Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Cut text file in place
Top Forums Shell Programming and Scripting Cut text file in place Post 302833599 by Corona688 on Wednesday 17th of July 2013 12:26:38 PM
Old 07-17-2013
In general, 'in place' almost never is, because files do not work that way. You cannot tell a disk 'snip this line here, change that text there, and make it all line up properly'. You get to seek, overwrite, and truncate, and that's it.

And that is what you need to do here -- truncate. Figure out exactly what byte you need the file to stop at, seek to that point, then truncate the rest. What languages can you use? I'm not sure you can do this in pure shell.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

How to cut a text file at a certain spot?

Say I do a date command and get the time from 15 minutes ago. I have a text file with the date printed out every minute or so and I want to cut the file at the date stamp given to me by the 15 minute ago time stamp. Is there an easy way to do this? Example: date +%M gives me 56 I... (2 Replies)
Discussion started by: LordJezo
2 Replies

2. Shell Programming and Scripting

Perl - Enter text in a file in a place.

Hi, I have a simple question: I need to enter some text in a text file at a certain place via perl. I would first need to find that specific text in the file and then I would like to insert a line after that particular line. Say I have this text file: I am a great Perl Programmer I... (1 Reply)
Discussion started by: som.nitk
1 Replies

3. Shell Programming and Scripting

Cut big text file into 2

I have a big text file. I want to cut it into 2 pieces at known point or I know the pattern of the contents from where it can separate the files. Is there any quick command/solution? (4 Replies)
Discussion started by: sandy221
4 Replies

4. UNIX for Dummies Questions & Answers

Cut text from a file

How can I cut the text of definite length say from line no. 20 to 1000? It is trivial ques, but I am very new to Unix. Thanks :) (3 Replies)
Discussion started by: JackR
3 Replies

5. Shell Programming and Scripting

How to get awk to edit in place and join all lines in text file

Hi, I lack the utter fundamentals on how to craft an awk script. I have hundreds of text files that were mangled by .doc format so all the lines are broken up so I need to join all of the lines of text into a single line. Normally I use vim command "ggVGJ" to join all lines but with so many... (3 Replies)
Discussion started by: n00ti
3 Replies

6. Shell Programming and Scripting

Inserting text into a file but searching for the place to put it!

Hi I would love a bit of help with a problem im having with a script. I need to insert a line of text which is saved in a variable called $fwInsert into a file whos name is saved in a variable called $server but it needs to be in a certain order. The file is a forward file for a network and... (12 Replies)
Discussion started by: KatieV
12 Replies

7. Shell Programming and Scripting

Cut text from a file and remove

Hello Friends, I am stuck with the below problem.Any help will be appreciated. I have a file which has say 100 lines. On the second last line I have a line from which i want to remove certain characters.. e.g CAST(CAST( A as varchar(50)) || ',' || CAST(CAST( B as varchar(50)) || ',' ||... (8 Replies)
Discussion started by: vital_parsley
8 Replies

8. UNIX for Advanced & Expert Users

Place the results of a CUT command into a variable

I am being passed a file in UNIX, ie: variable.txt I need to extract the first part of the file content, up to the period, content ie: common_dir.second_output cut -d'.' -f1 /content/stores/variable.txt I then need to utilize the results to create a variable ($1), and test on that... (4 Replies)
Discussion started by: talonbow
4 Replies

9. Shell Programming and Scripting

awk to place specific contents filename within text file

I am trying to use awk to place the contens of a filename in $1 and $2 followed by the data in the text file. Basically, put the filename within the text file. There are over 1000 files in the directory and as of now each file is saved with a unique name but it is not within the file. Thank you... (10 Replies)
Discussion started by: cmccabe
10 Replies

10. Shell Programming and Scripting

Modifying text file records, find data in one place in the record and print it elsewhere

Hello, I have some text data that is in the form of multi-line records. Each record ends with the string $$$$ and the next record starts on the next line. RDKit 2D 15 14 0 0 0 0 0 0 0 0999 V2000 5.4596 2.1267 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 ... (5 Replies)
Discussion started by: LMHmedchem
5 Replies

LEARN ABOUT LINUX

truncate

TRUNCATE(1)							   User Commands						       TRUNCATE(1)

NAME

       truncate - shrink or extend the size of a file to the specified size

SYNOPSIS

       truncate OPTION... FILE...

DESCRIPTION

       Shrink or extend the size of each FILE to the specified size

       A FILE argument that does not exist is created.

       If  a  FILE  is	larger than the specified size, the extra data is lost.  If a FILE is shorter, it is extended and the extended part (hole)
       reads as zero bytes.

       Mandatory arguments to long options are mandatory for short options too.

       -c, --no-create
	      do not create any files

       -o, --io-blocks
	      treat SIZE as number of IO blocks instead of bytes

       -r, --reference=FILE
	      use this FILE's size

       -s, --size=SIZE
	      use this SIZE

       --help display this help and exit

       --version
	      output version information and exit

       SIZE may be (or may be an integer optionally followed by) one of following: KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T,
       P, E, Z, Y.

       SIZE  may also be prefixed by one of the following modifying characters: `+' extend by, `-' reduce by, `<' at most, `>' at least, `/' round
       down to multiple of, `%' round up to multiple of.

       Note that the -r and -s options are mutually exclusive.

AUTHOR

       Written by Padraig Brady.

REPORTING BUGS

       Report truncate bugs to bug-coreutils@gnu.org
       GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
       General help using GNU software: <http://www.gnu.org/gethelp/>
       Report truncate translation bugs to <http://translationproject.org/team/>

COPYRIGHT

       Copyright (C) 2010 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

       dd(1), truncate(2), ftruncate(2)

       The full documentation for truncate is maintained as a Texinfo manual.  If the info and truncate programs are properly  installed  at  your
       site, the command

	      info coreutils 'truncate invocation'

       should give you access to the complete manual.

GNU coreutils 8.5						   February 2011						       TRUNCATE(1)
All times are GMT -4. The time now is 06:10 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy