Linux Commands Flashcards

1
Q

aspell

A

Checks a file for spelling errors

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2
Q

bzip2

A

Compresses or decompresses files—page 615

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3
Q

cat

A

Joins and displays files

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4
Q

cmp

A

Compares two files

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5
Q

comm

A

Compares sorted files

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6
Q

cp

A

cp Copies files

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7
Q

cpio

A

Creates an archive, restores files from an archive, or copies a directory
hierarchy

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8
Q

cut

A

Selects characters or fields from input lines

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9
Q

dd

A

Converts and copies a file

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10
Q

diff

A

Displays the differences between two text files

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11
Q

ditto

A

Copies files and creates and unpacks archives

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12
Q

find

A

Finds files based on criteria

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13
Q

fmt

A

Formats text very simply

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14
Q

grep

A

Searches for a pattern in files

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15
Q

gzip

A

Compresses or decompresses files

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16
Q

head

A

Displays the beginning of a file

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17
Q

less

A

Displays text files, one screen at a time

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18
Q

ln

A

Makes a link to a file

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19
Q

lpr

A

Sends files to printers

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20
Q

ls

A

Displays information about one or more files

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21
Q

man

A

Displays documentation for commands

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22
Q

mkdir

A

Creates a directory

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23
Q

mv

A

Renames or moves a file

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24
Q

od

A

Dumps the contents of a file

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25
Q

open

A

Opens files, directories, and URLs

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26
Q

otool

A

Displays object, library, and executable files

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27
Q

paste

A

Joins corresponding lines from files

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28
Q

pax

A

Creates an archive, restores files from an archive, or copies a directory
hierarchy

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29
Q

plutil

A

Manipulates property list files

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30
Q

pr

A

Paginates files for printing

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31
Q

rm

A

Removes a file (deletes a link)

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32
Q

rmdir

A

Removes directories

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33
Q

sed

A

Edits a file noninteractively

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34
Q

sort

A

Sorts and/or merges files

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35
Q

split

A

Divides a file into sections

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36
Q

strings

A

Displays strings of printable characters

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37
Q

tail

A

Displays the last part (tail) of a file

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38
Q

tar

A

Stores or retrieves files to/from an archive file

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39
Q

touch

A

Creates a file or changes a file’s access and/or modification time

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40
Q

uniq

A

Displays unique lines

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41
Q

wc

A

Displays the number of lines, words, and bytes

42
Q

ftp

A

Transfers files over a network

43
Q

rcp

A

Copies one or more files to or from a remote system

44
Q

rlogin

A

Logs in on a remote system

45
Q

rsh

A

rsh Executes commands on a remote system

46
Q

rsync

A

Copies files and directory hierarchies securely over a network

47
Q

scp

A

Securely copies one or more files to or from a remote system

48
Q

ssh

A

Securely executes commands on a remote system

49
Q

telnet

A

Connects to a remote system over a network

50
Q

cd

A

Changes to another working directory

51
Q

chgrp

A

Changes the group associated with a file

52
Q

chmod

A

Changes the access mode (permissions) of a file

53
Q

chown

A

Changes the owner of a file and/or the group the file is associated
with

54
Q

date

A

Displays or sets the system time and date

55
Q

df

A

Displays disk space usage

56
Q

dscl

A

Displays and manages Directory Service information

57
Q

dmesg

A

Displays kernel messages

58
Q

du

A

Displays information on disk usage by directory hierarchy and/or
file

59
Q

file

A

file Displays the classification of a file

60
Q

finger

A

Displays information about users

61
Q

GetFileInfo

A

Displays file attributes

62
Q

kill

A

Terminates a process by PID

63
Q

killall

A

Terminates a process by name

64
Q

nice

A

Changes the priority of a command

65
Q

nohup

A

Runs a command that keeps running after you log out

66
Q

ps

A

Displays process status

67
Q

renice

A

Changes the priority of a process

68
Q

SetFile

A

Sets file attributes

69
Q

sleep

A

Creates a process that sleeps for a specified interval

70
Q

stat

A

Displays information about files

71
Q

stty

A

Displays or sets terminal parameters

72
Q

sysctl

A

Displays and alters kernel variables

73
Q

top

A

Dynamically displays process status

74
Q

umask

A

Establishes the file-creation permissions mask

75
Q

w

A

Displays information about system users

76
Q

which

A

Shows where in PATH a command is located

77
Q

who

A

Displays information about logged-in users

78
Q

awk

A

Searches for and processes patterns in a file

79
Q

configure

A

Configures source code automatically

80
Q

gawk

A

Searches for and processes patterns in a file

81
Q

gcc

A

Compiles C and C++ programs

82
Q

make

A

Keeps a set of programs current

83
Q

mawk

A

Searches for and processes patterns in a file

84
Q

at

A

Executes commands at a specified time

85
Q

cal

A

Displays a calendar

86
Q

crontab

A

Maintains crontab files

87
Q

diskutil

A

Checks, modifies, and repairs local volumes

88
Q

echo

A

Displays a message

89
Q

expr

A

Evaluates an expression

90
Q

fsck

A

Checks and repairs a filesystem

91
Q

launchctl

A

Controls the launchd daemon

92
Q

mkfs

A

Creates a filesystem on a device

93
Q

Mtools

A

Uses DOS-style commands on files and directories

94
Q

tee

A

Copies standard input to standard output and one or more files

95
Q

test

A

Evaluates an expression

96
Q

tr

A

Replaces specified characters

97
Q

tty

A

Displays the terminal pathname

98
Q

tune2fs

A

Changes parameters on an ext2, ext3, or ext4 filesystem

99
Q

xargs

A

Converts standard input to command lines

100
Q

Common Options

A

Several GNU utilities share the options listed in Table V-2. The utilities that use
these options are marked as such.
Table V-2
Common command-line options
Option Effect
– A single hyphen appearing in place of a filename instructs the utility to accept
standard input in place of the file.
–– A double hyphen marks the end of the options on a command line. You can fol-
low this option with an argument that begins with a hyphen. Without this
option the utility assumes that an argument that begins with a hyphen is an
option.
––help Displays a help message for the utility. Some of these messages are quite long;
using a pipe, you can send the output through less to display it one screen at
a time. For example, you could give the command ls ––help | less. Alterna-
tively, you can send the output through a pipe to grep if you are looking for
specific information. For example, you could give the following command to
get information on the –d option to ls : ls ––help | grep –– –d. See the pre-
ceding entry in this table for information on the double hyphen.
––version Displays version information for the utility.