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l ess typing l ess typing

l ess typing - PowerPoint Presentation

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l ess typing - PPT Presentation

History history lists recent commands ltnumbergt redoes that command ltpartialgt redoes the most recent command that started with ltpartial gt letters Globbing Describe to the shell not OS sets of file names with patterns ID: 532463

file1 file lines files file file1 files lines displays letters matches means txt zip pattern cat file2 regular expressions

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Presentation Transcript

Slide1

less typing

History

history

lists recent commands

.

!

<number>

redoes that command

!<partial>

redoes the most recent command that started with

<partial

>

letters

Globbing

Describe to the shell (not OS) sets of file names with patterns

~

means the home directory

?

means any character

*

means any string (including empty)

[<letters>]

means any one of the <letters> (except ...), which can also be a range

^

negates some glob expressions

File

name completion

Many

shells

provide

file name

completion: Use

tab

key to

expand partial file namesSlide2

locate a file

l

ocate

unix_class_files.zip locate unix_class

locate the path for file unix_class_files.zip

l

ocate the path for all the files containing

unix_classSlide3

grouping & compressing files

t

ar –

cz

vf

file.tar.gz

file1 file2

tar

xzvf file.tar.gz

groups and compresses files

ungroups and decompresses

file.tar.gzSlide4

grouping & compressing files

g

zip

file1zip file.zip f1 f2unzip

file.zipgunzip file.gz

compresses

file1

into

file.gz

compresses

f1 and f2 into file.zip

decompresses file.zip

decompresses

file.gzSlide5

Text handling commandsSlide6

cat, less

cat file1

displays

file1 as a whole

less file1

displays

file1

page-by-page



allows scrolling through the file

< or g

goes to the beginning> or G goes to the endspace page down

b

page up

/pattern

search pattern

n

find next one

N

find previous

q

quit

cat file1 file2 file3

c

oncatenates and displays

file1

,

file2

and file3 as a whole

cat file1 file2 file3 > out.txt

concatenates file1, file2 and file3 and redirects output to file out.txt

cat file4 file5 >> out.txt

concatenates file4 and file5 and appends output to file out.txtSlide7

head, tail

head file1

d

isplays the first 10 lines of file1

head –n 20 file1

d

isplays the first 20 lines of

file1

tail file1

d

isplays the last 10 lines of file1

tail –n 20 file1

d

isplays the last 20 lines of

file1Slide8

regular expressions - grep

Regular expressions

describe

sets of strings with patterns (not the same as globbing)A normal character matches

itself. matches any normal characterA range

[<letters>]

matches any one of the

<letters

>,

which

can also be a range [^<letters>] matches any not one of the <letters>? after a pattern makes it optional+

after a pattern matches one or more repetitions* after a pattern matches any number of repetitions

{

<N>}

after a pattern matches

<N>

repetitions in

regular expressions

^

means the start of the

line

$

means the end of the

line

(

)

s round a

regular expression makes

it one thing to which repetition and placement options can be applied.

grep finds lines in files that match limited regular expressions.grep ‘^>’

file.txt

displays lines in file.txt that start with a >grep -c ‘^+$’ *fastq

displays lines in all fasta files that are composed of a single

+