File Handling And Bash

Question 1

dd

Answer 1

Copies & converts files, often for arbitrary size.
if=
of=
bs: block size
count:amount of block size

Question 2

tar

Answer 2

Wrap up files & folders into archive file without compression.
-c: creating archive
-f: tar file name
-j: bzip2 compression flag
Unzipped by bunzip2, also compressed with bzip2
-t: tar contents
-v: verbose
-x: xpand
-z: gzip compression & decompression flag
Gunzip and gzip
NOTE ALSO: xz and unxz

Question 3

find

Answer 3

• name
• ctime
• atime
• empty
• exec []{}|;
• type
• newer

Question 4

zcat

Answer 4

View gzip compressed.

Similar bzcat and xzcat

Question 5

nl

Answer 5

#of lines without blanks.
-b: include blank lines

Question 6

wc

Answer 6

Word count: line count (all), words in file, byte count, name

• c: for bytes
• l : for line numbers
• w: words only

Question 7

od

Answer 7

Octal dump.
Col. 1 byte offset, next octal info.
-a: ASCII
-c: char format

Question 8

Checksums

Answer 8

md5sum, sha256sum, sha512sum.
Redirect output to appropriate named file for test.
Ex: .md5, .sha256, .sha512
-c: check with file storing sum and file name relevant to.

Question 9

sort

Answer 9

Sort &/or merge lines of file, defaulting to first column.

• k: specify column to use as delimiter
• n: detects full number
• t: explicit delimiter char(s)
• u: only unique lines printed

Question 10

uniq

Answer 10

Condenses repeated lines to identify unique. Only directly adjacent default
-c: counts of merges displayed
-u: count
—group: grouping

Question 11

tr

Answer 11

Translate/swap chars to another in output. Strongly quoted

-d: delete given char

Question 12

cut

Answer 12

Extract col./data fields from file

• d: delimiter. Strong quotes
• f: field in , form

Question 13

paste

Answer 13

Similar to cat, but in parallel default delimiter tab.

• d <strong>: specified delimiter to add.</strong>
• s: serial paste<strong></strong></strong>

Question 14

sed

Answer 14

Stream editor. Alter text in file, search & replace words, directives in strong quotes.ex: ‘s/desktop/workstation/‘: substitutes desktop with workstation. g/ to change all.
-i: permanent

Question 15

split

Answer 15

Breaks file into pieces. Normally 1000 lines per piece
-b: byte number
—verbose
-n: number of individual files

Question 16

Man page numbers

Answer 16

1=executable pkgs/small cud’s
2=syscalls
3=lib calls
4=special files
5=file formats & conventions
6=games
7=misc items & conventions
8=sysadmin cmds 
9=nonstandard kernel routines