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1
vote
1answer
39 views
POSIX head and tail not feature equivalent
The documentation for POSIX tail's -n option says that
The origin for counting shall be 1; that is, -n +1 represents the first line of the file, -n -1 the last.
So tail -n 10 (used later on the ...
6
votes
1answer
53 views
How to do `head` and `tail` on null-delimited input in bash?
find command can output names of files as a null-delimited strings (if -print0 is provided), and xargs can consume them with -0 option turned on. But in between, it's hard to manipulate that ...
1
vote
1answer
30 views
head command options and reading man files
I have two environments: Mac and Linux.
I wonder about the head command:
it can show just 2 lines of text if I invoke it like so:
vim --version | head -2
I saw this online and ran to the man page ...
4
votes
0answers
66 views
Combing head and tail in a single call via pipe [duplicate]
On a regular basis, I am piping the output of some program to either head or tail.
Now, suppose that I want to see the first AND last 10 lines of piped output, such that I could do something like
...
2
votes
1answer
98 views
Why can't I trim a file using `head`? [duplicate]
Given a file, foo.txt:
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2
3
4
5
Say we want to change it to contain:
1
2
3
Why does head -n3 foo.txt > foo.txt leave foo.txt empty?
3
votes
2answers
252 views
Why does Subversion give a broken pipe error when piped into head?
If I do a
svn log | head
after the tenth line of output I get an error message:
svn: Write error: Broken pipe
What's going on here? I haven't seen any other command do this when used with head. ...
0
votes
1answer
57 views
Redirecting head output for update hosts file [duplicate]
Possible Duplicate:
How can I make iconv replace the input file with the converted output?
I'm writing a script to change the content of my hosts file but I got stuck on the head output ...
11
votes
6answers
1k views
Command to display first few and last few lines of a file
I have a file with many rows, and each row has a timestamp at the starting, like
[Thread-3] (21/09/12 06:17:38:672) logged message from code.....
So, I frequently check 2 things from this log file.
...
6
votes
4answers
3k views
cat line X to line Y on a huge file
Say I have a huge text file (>2GB) and I just want to cat the lines X to Y (e.g. 57890000 to 57890010).
From what I understand I can do this by piping head into tail or viceversa, i.e.
head -A ...
6
votes
1answer
248 views
Peculiar piping grep/head behavior
I'm helping the netadmin here with a perl regex to automate operating on some snapshots from our SAN and our scripts does stuff like this:
varinit1=$(iscsiadm -m session | grep rbmsdata1 | head -n1 | ...
5
votes
2answers
401 views
Why does `cat`ing a file into itself erase it? [duplicate]
Possible Duplicate:
IO redirection and the head command
I just wanted to remove all but the first line of a file. I did this:
head -1 foo.txt
... and verified that I saw only the first ...
2
votes
2answers
677 views
How to execute this particular shell command from Python?
OK, so, I have this non-functional shell script, which I am rewriting piece by piece in python, except I am getting an "unexpected "|" error" from the shell (see below):
#/bin/sh
LINES=`cat $@ | wc ...
17
votes
4answers
3k views
How to obtain inverse behavior for `tail` and `head`?
Is there a way to head/tail a document and get the reverse output; because you don't know how many lines there are in a document?
I.e. I just want to get everything but the first 2 lines of foo.txt ...
