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site/pages/cmd/advanced
head-tail.htmlpaste.html

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site/pages/cmd/advanced/head-tail.html
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@ -4,48 +4,39 @@ author: Agostino Monti
category-page: advanced category-page: advanced
category-title: Advanced commands category-title: Advanced commands
tags: head tail text file tags: head tail text file
title: head-tail title: head and tail
--- ---
<br> The <code>head</code> command reads the first few lines of any text given to it as an input
<br> and writes them to standard output.<br>
<h3><code>head</code></h3> If more than one input file is provided, head will return the first ten lines
<p>The <code>head</code> command reads the first few lines of any text given to it as an input from each file, precede each set of lines by the name of the file and separate
and writes them to standard output. each set of lines by one vertical space.
If more than one input file is provided, head will return the first ten lines
from each file, precede each set of lines by the name of the file and separate
each set of lines by one vertical space. </p>
<br>
<h3><code>tail</code></h3> <pre>
<p>The tail command is similar to the head command head [flags] [file1] [file2] ...
except that it reads the final lines in files rather than the first lines.</p> </pre>
<h4>Examples</h4> The <code>tail</code> command is similar to the <code>head</code> command
<p><pre> except that it reads the final lines in files rather than the first lines.
head file1.txt <br>
head file1.txt file2.txt <br>
tail fail1.txt</pre></p>
<pre>
tail [flags] [file1] [file2] ...
</pre>
<h3>flags</h3> <h3>Flags</h3>
<ul>
<li>The <code>-n</code> option can be used followed by an integer indicating the number of lines desired.
-n is a very tolerant option, it is not necessary for the integer to directly
follow it without a space in between. In fact, the letter <i>n</i> does not
even need to be used at all. Just the hyphen and the integer
(with no intervening space) are sufficient to tell head how many lines to return.
<h4>Examples</h4>
<pre>
head -n15 file1.txt <br>
head -n 15 file1.txt <br>
head -15 file1.txt</pre></li>
<li>The output from other commands can be sent via a pipe (represented by the vertical bar character) <ul>
to head to use as its input. The following sends the output from the ls command <li><b>-n</b>: can be used followed by number, which indicates the number of
to head, which, in turn, displays the first ten lines of the output that it receives from ls lines desired in the output. This flag can be used without <i>n</i>: the hyphen and the
<h4>Examples</h4> number (with no intervening space) are enough to tell head how many lines to return.
<pre> <pre>
ls | head </pre></li> head -n15 file1.txt <br>
head -n 15 file1.txt <br>
</ul> head -15 file1.txt</pre>
</li>
<li><b>-c</b>: similar to <i>-n</i> with the only difference being that the number stands for
bytes instead of the number of lines and the fact that it can't be used without explicitly
typing the <i>-c</i>.
</li>
</ul>

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---
layout: page
author: Agostino Monti
category-page: advanced
category-title: Advanced commands
tags: filie coluns analize
title: paste
---
The <code>paste</code> command is used to join files horizontally
(parallel merging) by outputting lines consisting of the sequentially corresponding
lines of each file specified, separated by tabs, to the standard output.<br>
Once involved, <code>paste</code> will read all its file arguments. For each corresponding line,
paste will append the contents of each file at that line to its output along with a tab.
When it has completed its operation for the last file, <code>paste</code> will output a newline
character and move on to the next line.
<pre>
paste [flags] [file1] [file2] ...
</pre>
<h3>Flags</h3>
<ul>
<li><code>-d</code> delimiters, which specifies a list of delimiters to be used instead of tabs
for separating consecutive values on a single line. Each delimiter is used in turn;
when the list has been exhausted, paste begins again at the first delimiter.
<pre>
paste -d "|" file1.txt file2.txt
paste -d "|," file1.txt file2.txt</pre>
</li>
<li><code>-s</code>, which causes paste to append the data in serial rather than in parallel;
that is, in a horizontal rather than vertical fashion.
</li>
</ul>