Questions tagged [head]

head is a program on Unix and Unix-like systems used to display the beginning of a text file or piped data.

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33 views

Command Line Number Line Not In Sync

I'm playing around with the command line. For some reason when I try to grab lines 439 - 445 the output I am getting is lines 375 - 381 instead. I use the tail command to jump to line 439 then use the ...
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1answer
20 views

Linux head/tail commands' man page does not show the '-LINES' argument

I have just read in a book that the command head -LINES displays the first LINES lines of a file. However, head's man page does not seem to reveal this is a legit argument. I'd like to know what I am ...
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1answer
92 views

How can I detect/remove special characters from this short text file?

This is the contents of a short text file created by an AppleScript written by someone else: Search time: Sunday April 28, 2019 at 07:21:07 Search complete. Nothing found. But, when I use cat I get ...
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1answer
64 views

Automatic head in ms-word

I’m creating a template in word and would like to include a text field in the cover for the title, something like "Document Title", that will be replaced by the user with the real title the want to ...
9
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1answer
14k views

tail/head all line except X last/first Lines

for example i have this file : cat myfile 1 2 3 4 5 i want to print all lines except first 2 line . output should be like this : tail -n $(( $(wc -l myfile | awk '{print $1}') - 2 )) myfile 3 4 5 ...
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1answer
7k views

How to echo only 1st line from 'curl' command output?

I'm trying to get only first line of the curl command output. (Sorry if this is confusing) Let's say, for an instance, i run simply: # curl http://localhost <!-- This is the hidden line i want to ...
3
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1answer
191 views

Head on very large files

I have 2 very big files (27G and 40G), which are output of dd command on a failing hard drive. I wanted to compare the first bytes to see if the 27G bytes is the begining/substring of the 40G. I ...
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1answer
996 views

How to grep for line numbers in a binary file?

I'm on Centos 5 Linux and using GNU grep v2.5.1 and looking at a 36GB log file. It is huge and I need to find around a million lines starting from the occurrence of a string 6307459 in the log file ...
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1answer
182 views

Head waits for full stdin before printing

When one runs ls | head head seems to wait for the full output of the piped command before printing to screen. This is undesirable when the command will take a very long time to run, such as when ...
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0answers
426 views

Copy huge file skipping first line using dd in Linux

I was trying to copy the content of a huge file (10GB) to another skipping the first line (as in head -n1). I tried multiple ways of head, tail, awk and sed. Settled on using tail -n+2 > ./xab.1 ...
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4answers
17k views

Creating a large file of random bytes quickly

I want to create a large file ~10G filled with zeros and random values. I have tried using: dd if=/dev/urandom of=10Gfile bs=5G count=10 it creates a file of about 2Gb and exits with a exit status 0....
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1answer
34 views

Using head to see up to a character

I have some C source files and a lot of them have a single, 1-line comment at the top that offers a short description of what that program does (I haven't done anything complex enough to warrant a ...
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1answer
553 views

Extracting part of a large SQL dump

Is there a way to chain commands like grep and head together to extract a portion of a file? The problem is that somewhere in my .sql file I have an old data that I need to compare to new data and I ...
1
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1answer
782 views

head and cat don't recognize Microsoft Excel text files

I have a large .xls file with 53760 rows and 19 columns. I saved it as Tab Delimited Text in order to pre-process it through command line tools and load it into R later. However, when I run head ...
1
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1answer
889 views

How to resolve conflicts when two binaries have the same name

Running OS X (10.9), I have a program called 'HEAD' in /Applications/XAMPP/xamppfiles/bin/, which is related to libwww-perl. The OS also has an unrelated program called 'head' in /usr/bin/ Since the ...
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1answer
908 views

head hangs or doesn't terminate on Linux

I'm using, (uname -a says) Linux ip-x-x-x-x 2.6.21.7-2.fc8xen-ec2-v1.0 #1 SMP Tue Sep 1 10:25:30 EDT 2009 x86_64 GNU/Linux. I've got a script, foo.sh with 100 lines of code and when I run head -...
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1answer
5k views

How to easily break up a text file into pieces smaller than a threshold?

I have some text files that are 100 to 300 MB in length that I want to view in Emacs, but my Emacs gets into some performance issues opening and traversing such large files. Therefore, I'm looking ...
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3answers
4k views

zcat | head : write error from large gz file

I was trying zcat to get only the first 1M lines of a compressed .gzip file into a new one. However, I get the following error: $ zcat path/to/R2.fq.gz | head -100 >R2.fqtest head: write error: ...
38
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6answers
49k views

Opposite of tail: all lines except the last n lines

How can I discard the last n lines of a file with a unix command line filter? That would be sort of the opposite of tail: tail discards the first n lines but pipes the rest through, but I want the ...
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1answer
134 views

What's the best way to view lines X through Y of a large file?

I have a very large text file and I want to view, say, lines 2000 through 2010 (with the line numbers included) I know one sort of roundabout way of getting there: sc -l [file] cat -n [file] | tail -...
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1answer
110 views

Read a Section of Lines from a File in Linux

I'm trying to export lines 100 to 1,000,100 from a file with 62 million lines. So far I've found this command: head -1100000 input > output But head does not take an offset option. Thoughts?
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1answer
2k views

Unix tool to output first n characters in an UTF-8 encoded file

I want to print the first 1000 characters in an UTF-8 encoded file. I know that the head tool can print the first n bytes of a file, but it may cut a character in the middle so that I get garbled ...
15
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4answers
12k views

Using 'head' or 'tail' on HUGE text file - 19 GB

I have a problem with viewing chunks of a very large text file. This file, approximately 19 GB, is obviously too big to view by any traditional means. I have tried head 1 and tail 1 (head -n 1 ...
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1answer
3k views

How to solve “Broken Pipe” error when using awk with head

I'm getting broken pipe errors from a command that does something like: ls -tr1 /a/path | awk -F '\n' -vpath=/prepend/path/ '{print path$1}' | head -n 50 Essentially I want to list (with absolute ...
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2answers
191 views

How to copy head of files to another folder, keeping tree structure?

I have a bunch of huge files (4GB+ each) with the same extension in a directory structure in a network drive, but am only interested in the first few bytes of each, so I'd like to copy them all to my ...
4
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2answers
5k views

Stopping after first line of output

I try to do the following in a Bash script: run a command (such as tail -f log_file), wait until a specific output arrives, then stop the command, and go on with the script. I tried the following, ...
3
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3answers
2k views

How to grab a random section in the middle of a huge file?

I have a huge log file of around 3.5 GB and would like to sample random sections in the middle of say 10 MB for the purpose of debugging what my application is doing. I could use head or tail ...