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<!doctypehtml><html class="sidebar-visible no-js light"lang=en><head><meta charset=UTF-8><title>Exercise solutions - CLI text processing with GNU Coreutils</title><meta content="text/html; charset=utf-8"http-equiv=Content-Type><meta content="Example based guide for specialized text processing with GNU Coreutils"name=description><meta content=width=device-width,initial-scale=1 name=viewport><meta content=#ffffff name=theme-color><meta content="CLI text processing with GNU Coreutils"property=og:title><meta content=website property=og:type><meta content="Example based guide for specialized text processing with GNU Coreutils"property=og:description><meta content=https://learnbyexample.github.io/cli_text_processing_coreutils/ property=og:url><meta content=https://raw.githubusercontent.com/learnbyexample/cli_text_processing_coreutils/main/images/cli_coreutils_ls.png property=og:image><meta content=1280 property=og:image:width><meta content=720 property=og:image:height><meta content=summary_large_image property=twitter:card><meta content=@learn_byexample property=twitter:site><link href=favicon.svg rel=icon><link rel="shortcut icon"href=favicon.png><link href=css/variables.css rel=stylesheet><link href=css/general.css rel=stylesheet><link href=css/chrome.css rel=stylesheet><link href=FontAwesome/css/font-awesome.css rel=stylesheet><link href=fonts/fonts.css rel=stylesheet><link href=highlight.css rel=stylesheet><link href=tomorrow-night.css rel=stylesheet><link href=ayu-highlight.css rel=stylesheet><link href=style.css rel=stylesheet><body><script>var path_to_root = "";
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html.classList.add("sidebar-" + sidebar);</script><nav aria-label="Table of contents"class=sidebar id=sidebar><div class=sidebar-scrollbox><ol class=chapter><li class="chapter-item expanded affix"><a href=cover.html>Cover</a><li class="chapter-item expanded affix"><a href=buy.html>Buy PDF/EPUB versions</a><li class="chapter-item expanded affix"><a href=preface.html>Preface</a><li class="chapter-item expanded"><a href=introduction.html><strong aria-hidden=true>1.</strong> Introduction</a><li class="chapter-item expanded"><a href=cat-tac.html><strong aria-hidden=true>2.</strong> cat and tac</a><li class="chapter-item expanded"><a href=head-tail.html><strong aria-hidden=true>3.</strong> head and tail</a><li class="chapter-item expanded"><a href=tr.html><strong aria-hidden=true>4.</strong> tr</a><li class="chapter-item expanded"><a href=cut.html><strong aria-hidden=true>5.</strong> cut</a><li class="chapter-item expanded"><a href=seq.html><strong aria-hidden=true>6.</strong> seq</a><li class="chapter-item expanded"><a href=shuf.html><strong aria-hidden=true>7.</strong> shuf</a><li class="chapter-item expanded"><a href=paste.html><strong aria-hidden=true>8.</strong> paste</a><li class="chapter-item expanded"><a href=pr.html><strong aria-hidden=true>9.</strong> pr</a><li class="chapter-item expanded"><a href=fold-fmt.html><strong aria-hidden=true>10.</strong> fold and fmt</a><li class="chapter-item expanded"><a href=sort.html><strong aria-hidden=true>11.</strong> sort</a><li class="chapter-item expanded"><a href=uniq.html><strong aria-hidden=true>12.</strong> uniq</a><li class="chapter-item expanded"><a href=comm.html><strong aria-hidden=true>13.</strong> comm</a><li class="chapter-item expanded"><a href=join.html><strong aria-hidden=true>14.</strong> join</a><li class="chapter-item expanded"><a href=nl.html><strong aria-hidden=true>15.</strong> nl</a><li class="chapter-item expanded"><a href=wc.html><strong aria-hidden=true>16.</strong> wc</a><li class="chapter-item expanded"><a href=split.html><strong aria-hidden=true>17.</strong> split</a><li class="chapter-item expanded"><a href=csplit.html><strong aria-hidden=true>18.</strong> csplit</a><li class="chapter-item expanded"><a href=expand-unexpand.html><strong aria-hidden=true>19.</strong> expand and unexpand</a><li class="chapter-item expanded"><a href=basename-dirname.html><strong aria-hidden=true>20.</strong> basename and dirname</a><li class="chapter-item expanded affix"><a href=what_next.html>What next?</a><li class="chapter-item expanded affix"><a class=active href=Exercise_solutions.html>Exercise solutions</a></li><br><hr><li class="chapter-item expanded"><i class="fa fa-github"id=git-repository-button></i><a href=https://github.com/learnbyexample/cli_text_processing_coreutils> Source code</a><li class="chapter-item expanded"><i class="fa fa-home"id=home-button></i><a href=https://learnbyexample.github.io/> My Blog</a><li class="chapter-item expanded"><i class="fa fa-book"id=book-button></i><a href=https://learnbyexample.github.io/books/> My Books</a><li class="chapter-item expanded"><i class="fa fa-envelope"id=mail-button></i><a href=https://learnbyexample.gumroad.com/l/learnbyexample-weekly> learnbyexample weekly</a><li class="chapter-item expanded"><i class="fa fa-twitter"id=twitter-button></i><a href=https://twitter.com/learn_byexample> Twitter</a></ol></div><div class=sidebar-resize-handle id=sidebar-resize-handle></div></nav><div class=page-wrapper id=page-wrapper><div class=page><div id=menu-bar-hover-placeholder></div><div class="menu-bar sticky bordered"id=menu-bar><div class=left-buttons><button aria-label="Toggle Table of Contents"title="Toggle Table of Contents"aria-controls=sidebar class=icon-button id=sidebar-toggle type=button><i class="fa fa-bars"></i></button><button aria-label="Change theme"title="Change theme"aria-controls=theme-list aria-expanded=false aria-haspopup=true class=icon-button id=theme-toggle type=button><i class="fa fa-paint-brush"></i></button><ul aria-label=Themes class=theme-popup id=theme-list role=menu><li role=none><button class=theme id=light role=menuitem>Light (default)</button><li role=none><button class=theme id=rust role=menuitem>Rust</button><li role=none><button class=theme id=coal role=menuitem>Coal</button><li role=none><button class=theme id=navy role=menuitem>Navy</button><li role=none><button class=theme id=ayu role=menuitem>Ayu</button></ul><button aria-label="Toggle Searchbar"title="Search. (Shortkey: s)"aria-controls=searchbar aria-expanded=false aria-keyshortcuts=S class=icon-button id=search-toggle type=button><i class="fa fa-search"></i></button></div><h1 class=menu-title>CLI text processing with GNU Coreutils</h1><div class=right-buttons><a aria-label=Blog href=https://learnbyexample.github.io title=Blog> <i class="fa fa-home"id=home-button></i> </a><a aria-label=Twitter href=https://twitter.com/learn_byexample title=Twitter> <i class="fa fa-twitter"id=twitter-button></i> </a><a aria-label="Git repository"title="Git repository"href=https://github.com/learnbyexample/cli_text_processing_coreutils> <i class="fa fa-github"id=git-repository-button></i> </a></div></div><div class=hidden id=search-wrapper><form class=searchbar-outer id=searchbar-outer><input placeholder="Search this book ..."aria-controls=searchresults-outer aria-describedby=searchresults-header id=searchbar name=searchbar type=search></form><div class="searchresults-outer hidden"id=searchresults-outer><div class=searchresults-header id=searchresults-header></div><ul id=searchresults></ul></div></div><script>document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
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});</script><div class=content id=content><main><div class=sidetoc><nav class=pagetoc></nav></div><h1 id=exercise-solutions><a class=header href=#exercise-solutions>Exercise solutions</a></h1><br><h1 id=cat-and-tac><a class=header href=#cat-and-tac>cat and tac</a></h1><p><strong>1)</strong> The given sample data has empty lines at the start and end of the input. Also, there are multiple empty lines between the paragraphs. How would you get the output shown below?<pre><code class=language-bash># note that there's an empty line at the end of the output
$ printf '\n\n\ndragon\n\n\n\nunicorn\nbee\n\n\n' | cat -sb
1 dragon
2 unicorn
3 bee
</code></pre><p><strong>2)</strong> Pass appropriate arguments to the <code>cat</code> command to get the output shown below.<pre><code class=language-bash>$ cat greeting.txt
Hi there
Have a nice day
$ echo '42 apples and 100 bananas' | cat - greeting.txt
42 apples and 100 bananas
Hi there
Have a nice day
</code></pre><p><strong>3)</strong> What does the <code>-v</code> option of the <code>cat</code> command do?<p>Displays nonprinting characters using the caret notation.<p><strong>4)</strong> Which options of the <code>cat</code> command do the following stand in for?<ul><li><code>-e</code> option is equivalent to <code>-vE</code><li><code>-t</code> option is equivalent to <code>-vT</code><li><code>-A</code> option is equivalent to <code>-vET</code></ul><p><strong>5)</strong> Will the two commands shown below produce the same output? If not, why not?<pre><code class=language-bash>$ cat fruits.txt ip.txt | tac
$ tac fruits.txt ip.txt
</code></pre><p>No. The first command concatenates the input files before reversing the content linewise. With the second command, each file content will be reversed separately.<p><strong>6)</strong> Reverse the contents of <code>blocks.txt</code> file as shown below, considering <code>----</code> as the separator.<pre><code class=language-bash>$ cat blocks.txt
----
apple--banana
mango---fig
----
3.14
-42
1000
----
sky blue
dark green
----
hi hello
$ tac -bs '----' blocks.txt
----
hi hello
----
sky blue
dark green
----
3.14
-42
1000
----
apple--banana
mango---fig
</code></pre><p><strong>7)</strong> For the <code>blocks.txt</code> file, write solutions to display only the last such group and last two groups.<pre><code class=language-bash># can also use: tac -bs '----' blocks.txt | awk '/----/ && ++c==2{exit} 1'
$ tac blocks.txt | sed '/----/q' | tac
----
hi hello
$ tac -bs '----' blocks.txt | awk '/----/ && ++c==3{exit} 1' | tac -bs '----'
----
sky blue
dark green
----
hi hello
</code></pre><p><strong>8)</strong> Reverse the contents of <code>items.txt</code> as shown below. Consider digits at the start of lines as the separator.<pre><code class=language-bash>$ cat items.txt
1) fruits
apple 5
banana 10
2) colors
green
sky blue
3) magical beasts
dragon 3
unicorn 42
$ tac -brs '^[0-9]' items.txt
3) magical beasts
dragon 3
unicorn 42
2) colors
green
sky blue
1) fruits
apple 5
banana 10
</code></pre><br><h1 id=head-and-tail><a class=header href=#head-and-tail>head and tail</a></h1><p><strong>1)</strong> Use appropriate commands and shell features to get the output shown below.<pre><code class=language-bash>$ printf 'carpet\njeep\nbus\n'
carpet
jeep
bus
# use the above 'printf' command for input data
$ c=$(printf 'carpet\njeep\nbus\n' | head -c3)
$ echo "$c"
car
</code></pre><p><strong>2)</strong> How would you display all the input lines except the first one?<pre><code class=language-bash>$ printf 'apple\nfig\ncarpet\njeep\nbus\n' | tail -n +2
fig
carpet
jeep
bus
</code></pre><p><strong>3)</strong> Which command would you use to get the output shown below?<pre><code class=language-bash>$ cat fruits.txt
banana
papaya
mango
$ cat blocks.txt
----
apple--banana
mango---fig
----
3.14
-42
1000
----
sky blue
dark green
----
hi hello
$ head -n2 fruits.txt blocks.txt
==> fruits.txt <==
banana
papaya
==> blocks.txt <==
----
apple--banana
</code></pre><p><strong>4)</strong> Use a combination of <code>head</code> and <code>tail</code> commands to get the 11th to 14th characters from the given input.<pre><code class=language-bash># can also use: tail -c +11 | head -c4
$ printf 'apple\nfig\ncarpet\njeep\nbus\n' | head -c14 | tail -c +11
carp
</code></pre><p><strong>5)</strong> Extract the starting six bytes from the input files <code>ip.txt</code> and <code>fruits.txt</code>.<pre><code class=language-bash>$ head -q -c6 ip.txt fruits.txt
it is banana
</code></pre><p><strong>6)</strong> Extract the last six bytes from the input files <code>fruits.txt</code> and <code>ip.txt</code>.<pre><code class=language-bash>$ tail -q -c6 fruits.txt ip.txt
mango
erish
</code></pre><p><strong>7)</strong> For the input file <code>ip.txt</code>, display except the last 5 lines.<pre><code class=language-bash>$ head -n -5 ip.txt
it is a warm and cozy day
listen to what I say
go play in the park
come back before the sky turns dark
</code></pre><p><strong>8)</strong> Display the third line from the given <code>stdin</code> data. Consider the NUL character as the line separator.<pre><code class=language-bash>$ printf 'apple\0fig\0carpet\0jeep\0bus\0' | head -z -n3 | tail -z -n1
carpet
</code></pre><br><h1 id=tr><a class=header href=#tr>tr</a></h1><p><strong>1)</strong> What's wrong with the following command?<pre><code class=language-bash>$ echo 'apple#banana#cherry' | tr # :
tr: missing operand
Try 'tr --help' for more information.
$ echo 'apple#banana#cherry' | tr '#' ':'
apple:banana:cherry
</code></pre><p>As a good practice, always quote the arguments passed to the <code>tr</code> command to avoid conflict with shell metacharacters. Unless of course, you need the shell to interpret them.<p><strong>2)</strong> Retain only alphabets, digits and whitespace characters.<pre><code class=language-bash>$ printf 'Apple_42 cool,blue\tDragon:army\n' | tr -dc '[:alnum:][:space:]'
Apple42 coolblue Dragonarmy
</code></pre><p><strong>3)</strong> Similar to rot13, figure out a way to shift digits such that the same logic can be used both ways.<pre><code class=language-bash>$ echo '4780 89073' | tr '0-9' '5-90-4'
9235 34528
$ echo '9235 34528' | tr '0-9' '5-90-4'
4780 89073
</code></pre><p><strong>4)</strong> Figure out the logic based on the given input and output data. Hint: use two ranges for the first set and only 6 characters in the second set.<pre><code class=language-bash>$ echo 'apple banana cherry damson etrog' | tr 'a-ep-z' '12345X'
1XXl5 21n1n1 3h5XXX 41mXon 5XXog
</code></pre><p><strong>5)</strong> Which option would you use to truncate the first set so that it matches the length of the second set?<p>The <code>-t</code> option is needed for this.<p><strong>6)</strong> What does the <code>*</code> notation do in the second set?<p>The <code>[c*n]</code> notation repeats a character <code>c</code> by <code>n</code> times. You can specify <code>n</code> in decimal or octal formats. If <code>n</code> is omitted, the character <code>c</code> is repeated as many times as needed to equalize the length of the sets.<p><strong>7)</strong> Change <code>:</code> to <code>-</code> and <code>;</code> to the newline character.<pre><code class=language-bash>$ echo 'tea:coffee;brown:teal;dragon:unicorn' | tr ':;' '-\n'
tea-coffee
brown-teal
dragon-unicorn
</code></pre><p><strong>8)</strong> Convert all characters to <code>*</code> except digit and newline characters.<pre><code class=language-bash>$ echo 'ajsd45_sdg2Khnf4v_54as' | tr -c '0-9\n' '*'
****45****2****4**54**
</code></pre><p><strong>9)</strong> Change consecutive repeated punctuation characters to a single punctuation character.<pre><code class=language-bash>$ echo '""hi..."", good morning!!!!' | tr -s '[:punct:]'
"hi.", good morning!
</code></pre><p><strong>10)</strong> Figure out the logic based on the given input and output data.<pre><code class=language-bash>$ echo 'Aapple noon banana!!!!!' | tr -cs 'a-z\n' ':'
:apple:noon:banana:
</code></pre><p><strong>11)</strong> The <code>books.txt</code> file has items separated by one or more <code>:</code> characters. Change this separator to a single newline character as shown below.<pre><code class=language-bash>$ cat books.txt
Cradle:::Mage Errant::The Weirkey Chronicles
Mother of Learning::Eight:::::Dear Spellbook:Ascendant
Mark of the Fool:Super Powereds:::Ends of Magic
$ <books.txt tr -s ':' '\n'
Cradle
Mage Errant
The Weirkey Chronicles
Mother of Learning
Eight
Dear Spellbook
Ascendant
Mark of the Fool
Super Powereds
Ends of Magic
</code></pre><br><h1 id=cut><a class=header href=#cut>cut</a></h1><p><strong>1)</strong> Display only the third field.<pre><code class=language-bash>$ printf 'tea\tcoffee\tchocolate\tfruit\n' | cut -f3
chocolate
</code></pre><p><strong>2)</strong> Display the second and fifth fields. Consider <code>,</code> as the field separator.<pre><code class=language-bash>$ echo 'tea,coffee,chocolate,ice cream,fruit' | cut -d, -f2,5
coffee,fruit
</code></pre><p><strong>3)</strong> Why does the below command not work as expected? What other tools can you use in such cases?<p><code>cut</code> ignores all repeated fields and the output is always presented in the ascending order.<pre><code class=language-bash># not working as expected
$ echo 'apple,banana,cherry,fig' | cut -d, -f3,1,3
apple,cherry
# expected output
$ echo 'apple,banana,cherry,fig' | awk -F, -v OFS=, '{print $3, $1, $3}'
cherry,apple,cherry
</code></pre><p><strong>4)</strong> Display except the second field in the format shown below. Can you construct two different solutions?<pre><code class=language-bash># solution 1
$ echo 'apple,banana,cherry,fig' | cut -d, --output-delimiter=' ' -f1,3-
apple cherry fig
# solution 2
$ echo '2,3,4,5,6,7,8' | cut -d, --output-delimiter=' ' --complement -f2
2 4 5 6 7 8
</code></pre><p><strong>5)</strong> Extract the first three characters from the input lines as shown below. Can you also use the <code>head</code> command for this purpose? If not, why not?<pre><code class=language-bash>$ printf 'apple\nbanana\ncherry\nfig\n' | cut -c-3
app
ban
che
fig
</code></pre><p><code>head</code> cannot be used because it acts on the input as a whole, whereas <code>cut</code> works line wise.<p><strong>6)</strong> Display only the first and third fields of the <code>scores.csv</code> input file, with tab as the output field separator.<pre><code class=language-bash>$ cat scores.csv
Name,Maths,Physics,Chemistry
Ith,100,100,100
Cy,97,98,95
Lin,78,83,80
$ cut -d, --output-delimiter=$'\t' -f1,3 scores.csv
Name Physics
Ith 100
Cy 98
Lin 83
</code></pre><p><strong>7)</strong> The given input data uses one or more <code>:</code> characters as the field separator. Assume that no field content will have the <code>:</code> character. Display except the second field, with <code>:</code> as the output field separator.<pre><code class=language-bash>$ cat books.txt
Cradle:::Mage Errant::The Weirkey Chronicles
Mother of Learning::Eight:::::Dear Spellbook:Ascendant
Mark of the Fool:Super Powereds:::Ends of Magic
$ <books.txt tr -s ':' | cut --complement -d':' --output-delimiter=' : ' -f2
Cradle : The Weirkey Chronicles
Mother of Learning : Dear Spellbook : Ascendant
Mark of the Fool : Ends of Magic
</code></pre><p><strong>8)</strong> Which option would you use to not display lines that do not contain the input delimiter character?<p>You can use the <code>-s</code> option to suppress such lines.<p><strong>9)</strong> Modify the command to get the expected output shown below.<pre><code class=language-bash>$ printf 'apple\nbanana\ncherry\n' | cut -c-3 --output-delimiter=:
app
ban
che
$ printf 'apple\nbanana\ncherry\n' | cut -c1,2,3 --output-delimiter=:
a:p:p
b:a:n
c:h:e
</code></pre><p><strong>10)</strong> Figure out the logic based on the given input and output data.<pre><code class=language-bash>$ printf 'apple\0fig\0carpet\0jeep\0' | cut -z --complement -c-2 | cat -v
ple^@g^@rpet^@ep^@
</code></pre><br><h1 id=seq><a class=header href=#seq>seq</a></h1><p><strong>1)</strong> Generate numbers from <code>42</code> to <code>45</code> in ascending order.<pre><code class=language-bash>$ seq 42 45
42
43
44
45
</code></pre><p><strong>2)</strong> Why does the command shown below produce no output?<p>You have to explicitly provide a negative step value to generate numbers in descending order.<pre><code class=language-bash># no output
$ seq 45 42
# expected output
$ seq 45 -1 42
45
44
43
42
</code></pre><p><strong>3)</strong> Generate numbers from <code>25</code> to <code>10</code> in descending order, with a step value of <code>5</code>.<pre><code class=language-bash>$ seq 25 -5 10
25
20
15
10
</code></pre><p><strong>4)</strong> Is the sequence shown below possible to generate with <code>seq</code>? If so, how?<pre><code class=language-bash>$ seq -w -s, 01.5 6
01.5,02.5,03.5,04.5,05.5
</code></pre><p><strong>5)</strong> Modify the command shown below to customize the output numbering format.<pre><code class=language-bash>$ seq 30.14 3.36 40.72
30.14
33.50
36.86
40.22
$ seq -f'%.3e' 30.14 3.36 40.72
3.014e+01
3.350e+01
3.686e+01
4.022e+01
</code></pre><br><h1 id=shuf><a class=header href=#shuf>shuf</a></h1><p><strong>1)</strong> What's wrong with the given command?<p><code>shuf</code> doesn't accept multiple input files. You can use <code>cat</code> to concatenate them first.<pre><code class=language-bash>$ shuf --random-source=greeting.txt fruits.txt books.txt
shuf: extra operand ‘books.txt’
Try 'shuf --help' for more information.
# expected output
$ cat fruits.txt books.txt | shuf --random-source=greeting.txt
banana
Cradle:::Mage Errant::The Weirkey Chronicles
Mother of Learning::Eight:::::Dear Spellbook:Ascendant
papaya
Mark of the Fool:Super Powereds:::Ends of Magic
mango
</code></pre><p><strong>2)</strong> What do the <code>-r</code> and <code>-n</code> options do? Why are they often used together?<p>The <code>-r</code> option helps if you want to allow input lines to be repeated. This option is usually paired with <code>-n</code> to limit the number of lines in the output. Otherwise, <code>shuf -r</code> will produce output lines indefinitely.<p><strong>3)</strong> What does the following command do?<p>The <code>-e</code> option is useful to specify multiple input lines as arguments to the command.<pre><code class=language-bash>$ shuf -e apple banana cherry fig mango
cherry
banana
mango
fig
apple
</code></pre><p><strong>4)</strong> Which option would you use to generate random numbers? Given an example.<p>The <code>-i</code> option helps generate random positive integers.<pre><code class=language-bash>$ shuf -n3 -i 100-200
128
177
193
</code></pre><p><strong>5)</strong> How would you generate 5 random numbers between <code>0.125</code> and <code>0.789</code> with a step value of <code>0.023</code>?<pre><code class=language-bash>$ seq 0.125 0.023 0.789 | shuf -n5
0.378
0.631
0.447
0.746
0.723
</code></pre><br><h1 id=paste><a class=header href=#paste>paste</a></h1><p><strong>1)</strong> What's the default delimiter character added by the <code>paste</code> command? Which option would you use to customize this separator?<p>Tab. You can use the <code>-d</code> option to change the delimiter between the columns.<p><strong>2)</strong> Will the following two commands produce equivalent output? If not, why not?<pre><code class=language-bash>$ paste -d, <(seq 3) <(printf '%s\n' item_{1..3})
1,item_1
2,item_2
3,item_3
$ printf '%s\n' {1..3},item_{1..3}
1,item_1
1,item_2
1,item_3
2,item_1
2,item_2
2,item_3
3,item_1
3,item_2
3,item_3
</code></pre><p>The outputs are not equivalent because brace expansion creates all combinations when multiple braces are used.<p><strong>3)</strong> Combine the two data sources as shown below.<pre><code class=language-bash>$ printf '1)\n2)\n3)'
1)
2)
3)
$ cat fruits.txt
banana
papaya
mango
$ paste -d '' <(printf '1)\n2)\n3)') fruits.txt
1)banana
2)papaya
3)mango
</code></pre><p><strong>4)</strong> Interleave the contents of <code>fruits.txt</code> and <code>books.txt</code>.<pre><code class=language-bash>$ paste -d'\n' fruits.txt books.txt
banana
Cradle:::Mage Errant::The Weirkey Chronicles
papaya
Mother of Learning::Eight:::::Dear Spellbook:Ascendant
mango
Mark of the Fool:Super Powereds:::Ends of Magic
</code></pre><p><strong>5)</strong> Generate numbers <code>1</code> to <code>9</code> in two different formats as shown below.<pre><code class=language-bash>$ seq 9 | paste -d: - - -
1:2:3
4:5:6
7:8:9
$ paste -d' : ' <(seq 3) /dev/null /dev/null <(seq 4 6) /dev/null /dev/null <(seq 7 9)
1 : 4 : 7
2 : 5 : 8
3 : 6 : 9
</code></pre><p><strong>6)</strong> Combine the contents of <code>fruits.txt</code> and <code>colors.txt</code> as shown below.<pre><code class=language-bash>$ cat fruits.txt
banana
papaya
mango
$ cat colors.txt
deep blue
light orange
blue delight
$ paste -d'\n' fruits.txt colors.txt | paste -sd,
banana,deep blue,papaya,light orange,mango,blue delight
</code></pre><br><h1 id=pr><a class=header href=#pr>pr</a></h1><p><strong>1)</strong> What does the <code>-t</code> option do?<p>The <code>-t</code> option turns off the pagination features like headers and trailers.<p><strong>2)</strong> Generate numbers <code>1</code> to <code>16</code> in two different formats as shown below.<pre><code class=language-bash>$ seq -w 16 | pr -4ats,
01,02,03,04
05,06,07,08
09,10,11,12
13,14,15,16
$ seq -w 16 | pr -4ts,
01,05,09,13
02,06,10,14
03,07,11,15
04,08,12,16
</code></pre><p><strong>3)</strong> How'd you solve the issue shown below?<pre><code class=language-bash>$ seq 100 | pr -37ats,
pr: page width too narrow
$ seq 100 | pr -J -w73 -37ats,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37
38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74
75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100
</code></pre><p><code>(N-1)*length(separator) + N</code> is the minimum page width you need, where <code>N</code> is the number of columns required. So, for <code>37</code> columns and a separator of length <code>1</code>, you'll need a minimum width of <code>73</code>. <code>-J</code> option ensures input lines aren't truncated.<p><strong>4)</strong> Combine the contents of <code>fruits.txt</code> and <code>colors.txt</code> in two different formats as shown below.<pre><code class=language-bash>$ cat fruits.txt
banana
papaya
mango
$ cat colors.txt
deep blue
light orange
blue delight
$ pr -mts' : ' fruits.txt colors.txt
banana : deep blue
papaya : light orange
mango : blue delight
$ pr -n:2 -mts, fruits.txt colors.txt
1:banana,deep blue
2:papaya,light orange
3:mango,blue delight
</code></pre><p><strong>5)</strong> What does the <code>-d</code> option do?<p>You can use the <code>-d</code> option to double space the input contents. That is, every newline character is doubled.</p><br><h1 id=fold-and-fmt><a class=header href=#fold-and-fmt>fold and fmt</a></h1><p><strong>1)</strong> What's the default wrap length of the <code>fold</code> and <code>fmt</code> commands?<p><code>80</code> bytes and <code>93%</code> of <code>75</code> columns respectively.<p><strong>2)</strong> Fold the given <code>stdin</code> data at 9 bytes.<pre><code class=language-bash>$ echo 'hi hello, how are you?' | fold -w9
hi hello,
how are
you?
</code></pre><p><strong>3)</strong> Figure out the logic based on the given input and output data using the <code>fold</code> command.<pre><code class=language-bash>$ cat ip.txt
it is a warm and cozy day
listen to what I say
go play in the park
come back before the sky turns dark
There are so many delights to cherish
Apple, Banana and Cherry
Bread, Butter and Jelly
Try them all before you perish
$ head -n2 ip.txt | fold -sw10
it is a
warm and
cozy day
listen to
what I say
</code></pre><p><strong>4)</strong> What does the <code>fold -b</code> option do?<p>The <code>-b</code> option will cause <code>fold</code> to treat tab, backspace, and carriage return characters as if they were a single byte character.<p><strong>5)</strong> How'd you get the expected output shown below?<pre><code class=language-bash># wrong output
$ echo 'fig appleseed mango pomegranate' | fold -sw7
fig
applese
ed
mango
pomegra
nate
# expected output
$ echo 'fig appleseed mango pomegranate' | fmt -w7
fig
appleseed
mango
pomegranate
</code></pre><p><strong>6)</strong> What do the options <code>-s</code> and <code>-u</code> of the <code>fmt</code> command do?<p>By default, the <code>fmt</code> command joins lines together that are shorter than the specified width. The <code>-s</code> option will disable this behavior.<p>The <code>-u</code> option changes multiple spaces to a single space. Excess spacing between sentences will be changed to two spaces.</p><br><h1 id=sort><a class=header href=#sort>sort</a></h1><p><strong>1)</strong> Default <code>sort</code> doesn't work for numbers. Which option would you use to get the expected output shown below?<pre><code class=language-bash>$ printf '100\n10\n20\n3000\n2.45\n' | sort -n
2.45
10
20
100
3000
</code></pre><p><strong>2)</strong> Which <code>sort</code> option will help you ignore case? <code>LC_ALL=C</code> is used here to avoid differences due to locale.<pre><code class=language-bash>$ printf 'Super\nover\nRUNE\ntea\n' | LC_ALL=C sort -f
over
RUNE
Super
tea
</code></pre><p><strong>3)</strong> The <code>-n</code> option doesn't work for all sorts of numbers. Which <code>sort</code> option would you use to get the expected output shown below?<pre><code class=language-bash># wrong output
$ printf '+120\n-1.53\n3.14e+4\n42.1e-2' | sort -n
-1.53
+120
3.14e+4
42.1e-2
# expected output
$ printf '+120\n-1.53\n3.14e+4\n42.1e-2' | sort -g
-1.53
42.1e-2
+120
3.14e+4
</code></pre><p><strong>4)</strong> What do the <code>-V</code> and <code>-h</code> options do?<p>The <code>-V</code> option is useful when you have a mix of alphabets and digits. It also helps when you want to treat digits after a decimal point as whole numbers, for example <code>1.10</code> should be greater than <code>1.2</code>.<p>Commands like <code>du</code> (disk usage) have the <code>-h</code> and <code>--si</code> options to display numbers with <a href=https://en.wikipedia.org/wiki/International_System_of_Units>SI suffixes</a> like <code>k</code>, <code>K</code>, <code>M</code>, <code>G</code> and so on. In such cases, you can use <code>sort -h</code> to order them.<p><strong>5)</strong> Is there a difference between <code>shuf</code> and <code>sort -R</code>?<p>The <code>sort -R</code> option will display the output in random order. Unlike <code>shuf</code>, this option will always place identical lines next to each other due to the implementation.<p><strong>6)</strong> Sort the <code>scores.csv</code> file numerically in ascending order using the contents of the second field. Header line should be preserved as the first line as shown below.<pre><code class=language-bash>$ cat scores.csv
Name,Maths,Physics,Chemistry
Ith,100,100,100
Cy,97,98,95
Lin,78,83,80
$ (sed -u '1q' ; sort -t, -k2,2n) < scores.csv
Name,Maths,Physics,Chemistry
Lin,78,83,80
Cy,97,98,95
Ith,100,100,100
</code></pre><p><strong>7)</strong> Sort the contents of <code>duplicates.csv</code> by the fourth column numbers in descending order. Retain only the first copy of lines with the same number.<pre><code class=language-bash>$ cat duplicates.csv
brown,toy,bread,42
dark red,ruby,rose,111
blue,ruby,water,333
dark red,sky,rose,555
yellow,toy,flower,333
white,sky,bread,111
light red,purse,rose,333
$ sort -t, -k4,4nr -u duplicates.csv
dark red,sky,rose,555
blue,ruby,water,333
dark red,ruby,rose,111
brown,toy,bread,42
</code></pre><p><strong>8)</strong> Sort the contents of <code>duplicates.csv</code> by the third column item. Use the fourth column numbers as the tie-breaker.<pre><code class=language-bash>$ sort -t, -k3,3 -k4,4n duplicates.csv
brown,toy,bread,42
white,sky,bread,111
yellow,toy,flower,333
dark red,ruby,rose,111
light red,purse,rose,333
dark red,sky,rose,555
blue,ruby,water,333
</code></pre><p><strong>9)</strong> What does the <code>-s</code> option provide?<p>The <code>-s</code> option is useful to retain the original order of input lines when two or more lines are deemed equal.<p><strong>10)</strong> Sort the given input based on the numbers inside the brackets.<pre><code class=language-bash>$ printf '(-3.14)\n[45]\n(12.5)\n{14093}' | sort -k1.2n
(-3.14)
(12.5)
[45]
{14093}
</code></pre><p><strong>11)</strong> What do the <code>-c</code>, <code>-C</code> and <code>-m</code> options do?<p>The <code>-c</code> option helps you spot the first unsorted entry in the given input. The uppercase <code>-C</code> option is similar but only affects the exit status. Note that these options will not work for multiple inputs.<p>The <code>-m</code> option is useful if you have one or more sorted input files and need a single sorted output file. This would be faster than normal sorting.</p><br><h1 id=uniq><a class=header href=#uniq>uniq</a></h1><p><strong>1)</strong> Will <code>uniq</code> throw an error if the input is not sorted? What do you think will be the output for the following input?<p><code>uniq</code> doesn't necessarily require the input to be sorted. Adjacent lines are used for comparison purposes.<pre><code class=language-bash>$ printf 'red\nred\nred\ngreen\nred\nblue\nblue' | uniq
red
green
red
blue
</code></pre><p><strong>2)</strong> Are there differences between <code>sort -u file</code> and <code>sort file | uniq</code>?<p>Yes. For example, you may need to sort based on some specific criteria and then identify duplicates based on the entire line contents. Here's an example:<pre><code class=language-bash># can't use sort -n -u here
$ printf '2 balls\n13 pens\n2 pins\n13 pens\n' | sort -n | uniq
2 balls
2 pins
13 pens
</code></pre><p><strong>3)</strong> What are the differences between <code>sort -u</code> and <code>uniq -u</code> options, if any?<p><code>sort -u</code> retains the first copy of duplicates that are deemed to be equal. <code>uniq -u</code> retains only the unique copies (i.e. not even a single copy of the duplicates will be part of the output).<p><strong>4)</strong> Filter the third column items from <code>duplicates.csv</code>. Construct three solutions to display only unique items, duplicate items and all duplicates.<pre><code class=language-bash>$ cat duplicates.csv
brown,toy,bread,42
dark red,ruby,rose,111
blue,ruby,water,333
dark red,sky,rose,555
yellow,toy,flower,333
white,sky,bread,111
light red,purse,rose,333
# unique
$ cut -d, -f3 duplicates.csv | sort | uniq -u
flower
water
# duplicates
$ cut -d, -f3 duplicates.csv | sort | uniq -d
bread
rose
# all duplicates
$ cut -d, -f3 duplicates.csv | sort | uniq -D
bread
bread
rose
rose
rose
</code></pre><p><strong>5)</strong> What does the <code>--group</code> option do? What customization features are available?<p>The <code>--group</code> options allows you to visually separate groups of similar lines with an empty line. This option can accept four values — <code>separate</code>, <code>prepend</code>, <code>append</code> and <code>both</code>. The default is <code>separate</code>, which adds a newline character between the groups. <code>prepend</code> will add a newline before the first group as well and <code>append</code> will add a newline after the last group. <code>both</code> combines the <code>prepend</code> and <code>append</code> behavior.<p><strong>6)</strong> Count the number of times input lines are repeated and display the results in the format shown below.<pre><code class=language-bash>$ s='brown\nbrown\nbrown\ngreen\nbrown\nblue\nblue'
$ printf '%b' "$s" | sort | uniq -c | sort -n
1 green
2 blue
4 brown
</code></pre><p><strong>7)</strong> For the input file <code>f1.txt</code>, retain only unique entries based on the first two characters of each line. For example, <code>abcd</code> and <code>ab12</code> should be considered as duplicates and neither of them will be part of the output.<pre><code class=language-bash>$ cat f1.txt
3) cherry
1) apple
2) banana
1) almond
4) mango
2) berry
3) chocolate
1) apple
5) cherry
$ sort f1.txt | uniq -u -w2
4) mango
5) cherry
</code></pre><p><strong>8)</strong> For the input file <code>f1.txt</code>, display only the duplicate items without considering the first two characters of each line. For example, <code>abcd</code> and <code>12cd</code> should be considered as duplicates. Assume that the third character of each line is always a space character.<pre><code class=language-bash>$ sort -k2 f1.txt | uniq -d -f1
1) apple
3) cherry
</code></pre><p><strong>9)</strong> What does the <code>-s</code> option do?<p>The <code>-s</code> option allows you to skip the first <code>N</code> characters (calculated as bytes).<p><strong>10)</strong> Filter only unique lines, but ignore differences due to case.<pre><code class=language-bash>$ printf 'cat\nbat\nCAT\nCar\nBat\nmat\nMat' | sort -f | uniq -iu
Car
</code></pre><br><h1 id=comm><a class=header href=#comm>comm</a></h1><p><strong>1)</strong> Get the common lines between the <code>s1.txt</code> and <code>s2.txt</code> files. Assume that their contents are already sorted.<pre><code class=language-bash>$ paste s1.txt s2.txt
apple banana
coffee coffee
fig eclair
honey fig
mango honey
pasta milk
sugar tea
tea yeast
$ comm -12 s1.txt s2.txt
coffee
fig
honey
tea
</code></pre><p><strong>2)</strong> Display lines present in <code>s1.txt</code> but not <code>s2.txt</code> and vice versa.<pre><code class=language-bash># lines unique to the first file
$ comm -23 s1.txt s2.txt
apple
mango
pasta
sugar
# lines unique to the second file
$ comm -13 s1.txt s2.txt
banana
eclair
milk
yeast
</code></pre><p><strong>3)</strong> Display lines unique to the <code>s1.txt</code> file and the common lines when compared to the <code>s2.txt</code> file. Use <code>==></code> to separate the output columns.<pre><code class=language-bash>$ comm -2 --output-delimiter='==>' s1.txt s2.txt
apple
==>coffee
==>fig
==>honey
mango
pasta
sugar
==>tea
</code></pre><p><strong>4)</strong> What does the <code>--total</code> option do?<p>Gives you the count of lines for each of the three columns.<p><strong>5)</strong> Will the <code>comm</code> command fail if there are repeated lines in the input files? If not, what'd be the expected output for the command shown below?<p>The number of duplicate lines in the common column will be minimum of the duplicate occurrences between the two files. Rest of the duplicate lines, if any, will be considered as unique to the file having the excess lines.<pre><code class=language-bash>$ cat s3.txt
apple
apple
guava
honey
tea
tea
tea
$ comm -23 s3.txt s1.txt
apple
guava
tea
tea
</code></pre><br><h1 id=join><a class=header href=#join>join</a></h1><blockquote><p><img alt=info src=./images/info.svg> Assume that the input files are already sorted for these exercises.</blockquote><p><strong>1)</strong> Use appropriate options to get the expected outputs shown below.<pre><code class=language-bash># no output
$ join <(printf 'apple 2\nfig 5') <(printf 'Fig 10\nmango 4')
# expected output 1
$ join -i <(printf 'apple 2\nfig 5') <(printf 'Fig 10\nmango 4')
fig 5 10
# expected output 2
$ join -i -a1 -a2 <(printf 'apple 2\nfig 5') <(printf 'Fig 10\nmango 4')
apple 2
fig 5 10
mango 4
</code></pre><p><strong>2)</strong> Use the <code>join</code> command to display only the non-matching lines based on the first field.<pre><code class=language-bash>$ cat j1.txt
apple 2
fig 5
lemon 10
tomato 22
$ cat j2.txt
almond 33
fig 115
mango 20
pista 42
# first field items present in j1.txt but not j2.txt
$ join -v1 j1.txt j2.txt
apple 2
lemon 10
tomato 22
# first field items present in j2.txt but not j1.txt
$ join -v2 j1.txt j2.txt
almond 33
mango 20
pista 42
</code></pre><p><strong>3)</strong> Filter lines from <code>j1.txt</code> and <code>j2.txt</code> that match the items from <code>s1.txt</code>.<pre><code class=language-bash>$ cat s1.txt
apple
coffee
fig
honey
mango
pasta
sugar
tea
# note that sort -m is used since the input files are already sorted
$ join s1.txt <(sort -m j1.txt j2.txt)
apple 2
fig 115
fig 5
mango 20
</code></pre><p><strong>4)</strong> Join the <code>marks_1.csv</code> and <code>marks_2.csv</code> files to get the expected output shown below.<pre><code class=language-bash>$ cat marks_1.csv
Name,Biology,Programming
Er,92,77
Ith,100,100
Lin,92,100
Sil,86,98
$ cat marks_2.csv
Name,Maths,Physics,Chemistry
Cy,97,98,95
Ith,100,100,100
Lin,78,83,80
$ join -t, --header marks_1.csv marks_2.csv
Name,Biology,Programming,Maths,Physics,Chemistry
Ith,100,100,100,100,100
Lin,92,100,78,83,80
</code></pre><p><strong>5)</strong> By default, the first field is used to combine the lines. Which options are helpful if you want to change the key field to be used for joining?<p>You can use <code>-1</code> and <code>-2</code> options followed by a field number to specify a different field number. You can use the <code>-j</code> option if the field number is the same for both the files.<p><strong>6)</strong> Join the <code>marks_1.csv</code> and <code>marks_2.csv</code> files to get the expected output with specific fields as shown below.<pre><code class=language-bash>$ join -t, --header -o 1.1,1.3,2.2,1.2 marks_1.csv marks_2.csv
Name,Programming,Maths,Biology
Ith,100,100,100
Lin,100,78,92
</code></pre><p><strong>7)</strong> Join the <code>marks_1.csv</code> and <code>marks_2.csv</code> files to get the expected output shown below. Use <code>50</code> as the filler data.<pre><code class=language-bash>$ join -t, --header -o auto -a1 -a2 -e '50' marks_1.csv marks_2.csv
Name,Biology,Programming,Maths,Physics,Chemistry
Cy,50,50,97,98,95
Er,92,77,50,50,50
Ith,100,100,100,100,100
Lin,92,100,78,83,80
Sil,86,98,50,50,50
</code></pre><p><strong>8)</strong> When you use the <code>-o auto</code> option, what'd happen to the extra fields compared to those in the first lines of the input data?<p>If you use <code>auto</code> as the argument for the <code>-o</code> option, first line of both the input files will be used to determine the number of output fields. If the other lines have extra fields, they will be discarded.<p><strong>9)</strong> From the input files <code>j3.txt</code> and <code>j4.txt</code>, filter only the lines are unique — i.e. lines that are not common to these files. Assume that the input files do not have duplicate entries.<pre><code class=language-bash>$ cat j3.txt
almond
apple pie
cold coffee
honey
mango shake
pasta
sugar
tea
$ cat j4.txt
apple
banana shake
coffee
fig
honey
mango shake
milk
tea
yeast
$ join -t '' -v1 -v2 j3.txt j4.txt
almond
apple
apple pie
banana shake
coffee
cold coffee
fig
milk
pasta
sugar
yeast
</code></pre><p><strong>10)</strong> From the input files <code>j3.txt</code> and <code>j4.txt</code>, filter only the lines are common to these files.<pre><code class=language-bash>$ join -t '' j3.txt j4.txt
honey
mango shake
tea
</code></pre><br><h1 id=nl><a class=header href=#nl>nl</a></h1><p><strong>1)</strong> <code>nl</code> and <code>cat -n</code> are always equivalent for numbering lines. True or False?<p>True if there are no empty lines in the input data. <code>cat -b</code> and <code>nl</code> are always equivalent.<p><strong>2)</strong> What does the <code>-n</code> option do?<p>You can use the <code>-n</code> option to customize the number formatting. The available styles are:<ul><li><code>rn</code> right justified with space fillers (default)<li><code>rz</code> right justified with leading zeros<li><code>ln</code> left justified with space fillers</ul><p><strong>3)</strong> Use <code>nl</code> to produce the two expected outputs shown below.<pre><code class=language-bash>$ cat greeting.txt
Hi there
Have a nice day
# expected output 1
$ nl -w3 -n'rz' greeting.txt
001 Hi there
002 Have a nice day
# expected output 2
$ nl -w3 -n'rz' -s') ' greeting.txt
001) Hi there
002) Have a nice day
</code></pre><p><strong>4)</strong> Figure out the logic based on the given input and output data.<pre><code class=language-bash>$ cat s1.txt
apple
coffee
fig
honey
mango
pasta
sugar
tea
$ nl -w2 -s'. ' -v15 -i-2 s1.txt
15. apple
13. coffee
11. fig
9. honey
7. mango
5. pasta
3. sugar
1. tea
</code></pre><p><strong>5)</strong> What are the three types of sections supported by <code>nl</code>?<p><code>nl</code> recognizes three types of sections with the following default patterns:<ul><li><code>\:\:\:</code> as header<li><code>\:\:</code> as body<li><code>\:</code> as footer</ul><p>These special lines will be replaced with an empty line after numbering. The numbering will be reset at the start of every section unless the <code>-p</code> option is used.<p><strong>6)</strong> Only number the lines that start with <code>----</code> in the format shown below.<pre><code class=language-bash>$ cat blocks.txt
----
apple--banana
mango---fig
----
3.14
-42
1000
----
sky blue
dark green
----
hi hello
$ nl -w2 -s') ' -bp'^----' blocks.txt
1) ----
apple--banana
mango---fig
2) ----
3.14
-42
1000
3) ----
sky blue
dark green
4) ----
hi hello
</code></pre><p><strong>7)</strong> For the <code>blocks.txt</code> file, determine the logic to produce the expected output shown below.<pre><code class=language-bash>$ nl -w1 -s'. ' -d'--' blocks.txt
1. apple--banana
2. mango---fig
1. 3.14
2. -42
3. 1000
1. sky blue
2. dark green
1. hi hello
</code></pre><p><strong>8)</strong> What does the <code>-l</code> option do?<p>The <code>-l</code> option controls how many consecutive empty lines should be considered as a single entry. Only the last empty line of such groupings will be numbered.<p><strong>9)</strong> Figure out the logic based on the given input and output data.<pre><code class=language-bash>$ cat all_sections.txt
\:\:\:
Header
teal
\:\:
Hi there
How are you
\:\:
banana
papaya
mango
\:
Footer
$ nl -p -w2 -s') ' -ha all_sections.txt
1) Header
2) teal
3) Hi there
4) How are you
5) banana
6) papaya
7) mango
Footer
</code></pre><br><h1 id=wc><a class=header href=#wc>wc</a></h1><p><strong>1)</strong> Save the number of lines in the <code>greeting.txt</code> input file to the <code>lines</code> shell variable.<pre><code class=language-bash>$ lines=$(wc -l <greeting.txt)
$ echo "$lines"
2
</code></pre><p><strong>2)</strong> What do you think will be the output of the following command?<p>Word count is based on whitespace separation.<pre><code class=language-bash>$ echo 'dragons:2 ; unicorns:10' | wc -w
3
</code></pre><p><strong>3)</strong> Use appropriate options and arguments to get the output as shown below. Also, why is the line count showing as <code>2</code> instead of <code>3</code> for the <code>stdin</code> data?<p>Line count is based on the number of newline characters. So, if the last line of the input doesn't end with the newline character, it won't be counted.<pre><code class=language-bash>$ printf 'apple\nbanana\ncherry' | wc -lc greeting.txt -
2 25 greeting.txt
2 19 -
4 44 total
</code></pre><p><strong>4)</strong> Use appropriate options and arguments to get the output shown below.<pre><code class=language-bash>$ printf 'greeting.txt\0scores.csv' | wc --files0-from=-
2 6 25 greeting.txt
4 4 70 scores.csv
6 10 95 total
</code></pre><p><strong>5)</strong> What is the difference between <code>wc -c</code> and <code>wc -m</code> options? And which option would you use to get the longest line length?<p>The <code>-c</code> option is useful to get the byte count. Use the <code>-m</code> option instead of <code>-c</code> if the input has multibyte characters.<pre><code class=language-bash># byte count
$ printf 'αλεπού' | wc -c
12
# character count
$ printf 'αλεπού' | wc -m
6
</code></pre><p>You can use the <code>-L</code> option to report the length of the longest line in the input (excluding the newline character of a line).<p><strong>6)</strong> Calculate the number of comma separated words from the <code>scores.csv</code> file.<pre><code class=language-bash>$ cat scores.csv
Name,Maths,Physics,Chemistry
Ith,100,100,100
Cy,97,98,95
Lin,78,83,80
$ <scores.csv tr ',' ' ' | wc -w
16
</code></pre><br><h1 id=split><a class=header href=#split>split</a></h1><blockquote><p><img alt=info src=./images/info.svg> Remove the output files after every exercise.</blockquote><p><strong>1)</strong> Split the <code>s1.txt</code> file 3 lines at a time.<pre><code class=language-bash>$ split -l3 s1.txt
$ head xa?
==> xaa <==
apple
coffee
fig
==> xab <==
honey
mango
pasta
==> xac <==
sugar
tea
$ rm xa?
</code></pre><p><strong>2)</strong> Use appropriate options to get the output shown below.<pre><code class=language-bash>$ echo 'apple,banana,cherry,dates' | split -t, -l1
$ head xa?
==> xaa <==
apple,
==> xab <==
banana,
==> xac <==
cherry,
==> xad <==
dates
$ rm xa?
</code></pre><p><strong>3)</strong> What do the <code>-b</code> and <code>-C</code> options do?<p>The <code>-b</code> option allows you to split the input by the number of bytes. This option also accepts suffixes such as <code>K</code> for <code>1024</code> bytes, <code>KB</code> for <code>1000</code> bytes, <code>M</code> for <code>1024 * 1024</code> bytes and so on.<p>The <code>-C</code> option is similar to the <code>-b</code> option, but it will try to break on line boundaries if possible. The break will happen before the given byte limit. If a line exceeds the given limit, it will be broken down into multiple parts.<p><strong>4)</strong> Display the 2nd chunk of the <code>ip.txt</code> file after splitting it 4 times as shown below.<pre><code class=language-bash>$ split -nl/2/4 ip.txt
come back before the sky turns dark
There are so many delights to cherish
</code></pre><p><strong>5)</strong> What does the <code>r</code> prefix do when used with the <code>-n</code> option?<p>This creates output files with interleaved lines.<p><strong>6)</strong> Split the <code>ip.txt</code> file 2 lines at a time. Customize the output filenames as shown below.<pre><code class=language-bash>$ split -l2 -a1 -d --additional-suffix='.txt' ip.txt ip_
$ head ip_*
==> ip_0.txt <==
it is a warm and cozy day
listen to what I say
==> ip_1.txt <==
go play in the park
come back before the sky turns dark
==> ip_2.txt <==
There are so many delights to cherish
==> ip_3.txt <==
Apple, Banana and Cherry
Bread, Butter and Jelly
==> ip_4.txt <==
Try them all before you perish
$ rm ip_*
</code></pre><p><strong>7)</strong> Which option would you use to prevent empty files in the output?<p>The <code>-e</code> option prevents empty files in the output.<p><strong>8)</strong> Split the <code>items.txt</code> file 5 lines at a time. Additionally, remove lines starting with a digit character as shown below.<pre><code class=language-bash>$ cat items.txt
1) fruits
apple 5
banana 10
2) colors
green
sky blue
3) magical beasts
dragon 3
unicorn 42
$ split -l5 --filter='grep -v "^[0-9]" > $FILE' items.txt
$ head xa?
==> xaa <==
apple 5
banana 10
green
==> xab <==
sky blue
dragon 3
unicorn 42
$ rm xa?
</code></pre><br><h1 id=csplit><a class=header href=#csplit>csplit</a></h1><blockquote><p><img alt=info src=./images/info.svg> Remove the output files after every exercise.</blockquote><p><strong>1)</strong> Split the <code>blocks.txt</code> file such that the first 7 lines are in the first file and the rest are in the second file as shown below.<pre><code class=language-bash>$ csplit -q blocks.txt 8
$ head xx*
==> xx00 <==
----
apple--banana
mango---fig
----
3.14
-42
1000
==> xx01 <==
----
sky blue
dark green
----
hi hello
$ rm xx*
</code></pre><p><strong>2)</strong> Split the input file <code>items.txt</code> such that the text before a line containing <code>colors</code> is part of the first file and the rest are part of the second file as shown below.<pre><code class=language-bash>$ csplit -q items.txt '/colors/'
$ head xx*
==> xx00 <==
1) fruits
apple 5
banana 10
==> xx01 <==
2) colors
green
sky blue
3) magical beasts
dragon 3
unicorn 42
$ rm xx*
</code></pre><p><strong>3)</strong> Split the input file <code>items.txt</code> such that the line containing <code>magical</code> and all the lines that come after are part of the single output file.<pre><code class=language-bash>$ csplit -q items.txt '%magical%'
$ cat xx00
3) magical beasts
dragon 3
unicorn 42
$ rm xx00
</code></pre><p><strong>4)</strong> Split the input file <code>items.txt</code> such that the line containing <code>colors</code> as well the line that comes after are part of the first output file.<pre><code class=language-bash>$ csplit -q items.txt '/colors/2'
$ head xx*
==> xx00 <==
1) fruits
apple 5
banana 10
2) colors
green
==> xx01 <==
sky blue
3) magical beasts
dragon 3