Linux Commands Flashcards
1
Q
aspell
A
Checks a file for spelling errors
2
Q
bzip2
A
Compresses or decompresses files—page 615
3
Q
cat
A
Joins and displays files
4
Q
cmp
A
Compares two files
5
Q
comm
A
Compares sorted files
6
Q
cp
A
cp Copies files
7
Q
cpio
A
Creates an archive, restores files from an archive, or copies a directory
hierarchy
8
Q
cut
A
Selects characters or fields from input lines
9
Q
dd
A
Converts and copies a file
10
Q
diff
A
Displays the differences between two text files
11
Q
ditto
A
Copies files and creates and unpacks archives
12
Q
find
A
Finds files based on criteria
13
Q
fmt
A
Formats text very simply
14
Q
grep
A
Searches for a pattern in files
15
Q
gzip
A
Compresses or decompresses files
16
Q
head
A
Displays the beginning of a file
17
Q
less
A
Displays text files, one screen at a time
18
Q
ln
A
Makes a link to a file
19
Q
lpr
A
Sends files to printers
20
Q
ls
A
Displays information about one or more files
21
Q
man
A
Displays documentation for commands
22
Q
mkdir
A
Creates a directory
23
Q
mv
A
Renames or moves a file
24
Q
od
A
Dumps the contents of a file
25
open
Opens files, directories, and URLs
26
otool
Displays object, library, and executable files
27
paste
Joins corresponding lines from files
28
pax
Creates an archive, restores files from an archive, or copies a directory
hierarchy
29
plutil
Manipulates property list files
30
pr
Paginates files for printing
31
rm
Removes a file (deletes a link)
32
rmdir
Removes directories
33
sed
Edits a file noninteractively
34
sort
Sorts and/or merges files
35
split
Divides a file into sections
36
strings
Displays strings of printable characters
37
tail
Displays the last part (tail) of a file
38
tar
Stores or retrieves files to/from an archive file
39
touch
Creates a file or changes a file’s access and/or modification time
40
uniq
Displays unique lines
41
wc
Displays the number of lines, words, and bytes
42
ftp
Transfers files over a network
43
rcp
Copies one or more files to or from a remote system
44
rlogin
Logs in on a remote system
45
rsh
rsh Executes commands on a remote system
46
rsync
Copies files and directory hierarchies securely over a network
47
scp
Securely copies one or more files to or from a remote system
48
ssh
Securely executes commands on a remote system
49
telnet
Connects to a remote system over a network
50
cd
Changes to another working directory
51
chgrp
Changes the group associated with a file
52
chmod
Changes the access mode (permissions) of a file
53
chown
Changes the owner of a file and/or the group the file is associated
with
54
date
Displays or sets the system time and date
55
df
Displays disk space usage
56
dscl
Displays and manages Directory Service information
57
dmesg
Displays kernel messages
58
du
Displays information on disk usage by directory hierarchy and/or
file
59
file
file Displays the classification of a file
60
finger
Displays information about users
61
GetFileInfo
Displays file attributes
62
kill
Terminates a process by PID
63
killall
Terminates a process by name
64
nice
Changes the priority of a command
65
nohup
Runs a command that keeps running after you log out
66
ps
Displays process status
67
renice
Changes the priority of a process
68
SetFile
Sets file attributes
69
sleep
Creates a process that sleeps for a specified interval
70
stat
Displays information about files
71
stty
Displays or sets terminal parameters
72
sysctl
Displays and alters kernel variables
73
top
Dynamically displays process status
74
umask
Establishes the file-creation permissions mask
75
w
Displays information about system users
76
which
Shows where in PATH a command is located
77
who
Displays information about logged-in users
78
awk
Searches for and processes patterns in a file
79
configure
Configures source code automatically
80
gawk
Searches for and processes patterns in a file
81
gcc
Compiles C and C++ programs
82
make
Keeps a set of programs current
83
mawk
Searches for and processes patterns in a file
84
at
Executes commands at a specified time
85
cal
Displays a calendar
86
crontab
Maintains crontab files
87
diskutil
Checks, modifies, and repairs local volumes
88
echo
Displays a message
89
expr
Evaluates an expression
90
fsck
Checks and repairs a filesystem
91
launchctl
Controls the launchd daemon
92
mkfs
Creates a filesystem on a device
93
Mtools
Uses DOS-style commands on files and directories
94
tee
Copies standard input to standard output and one or more files
95
test
Evaluates an expression
96
tr
Replaces specified characters
97
tty
Displays the terminal pathname
98
tune2fs
Changes parameters on an ext2, ext3, or ext4 filesystem
99
xargs
Converts standard input to command lines
100
Common Options
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.
