Commands Flashcards
1
Q
pwd
A
print the working directory
2
Q
echo STRING
A
display text from stdin
3
Q
time COMMAND
A
times how long COMMAND takes to execute
Three times are displayed: totalexecution time (aka real time); user CPU time; and system CPU time
4
Q
set
A
displays a wide variety of options relating to bash shell operation
These options are formatted much like environment variables; but they aren’t the same things. You can pass various options to set to have it affect a wide range of shell operations.
5
Q
exit
A
terminates any shell
Login shells are shell programs that are launched automatically when you initiate a text-mode login as opposed to those that run in xterm windows or other terminal emulators
6
Q
logout
A
terminates only login shells
Login shells are shell programs that are launched automatically when you initiate a text-mode login as opposed to those that run in xterm windows or other terminal emulators
7
Q
type COMMAND
A
tells you how a command you enter will be interpreted—as a built-in command; an external command; an alias; and so on
8
Q
history
A
displays all of the commands in the history
typically the latest 500 commands
9
Q
!!
A
display and execute the last command in your shell history
10
Q
!NUMBER
A
execute command NUMBER from the history
11
Q
$PATH
A
a directory list to search when you’re entering command or program names
12
Q
env
A
display environment variables
13
Q
unset VARNAME
A
unset an environment variable
14
Q
$PS1
A
the shell prompt
15
Q
man COMMAND
A
display the manual for COMMAND
16
Q
info COMMAND
A
hypertext formatted manual
17
Q
help COMMAND
A
a built in manual for built in commands
18
Q
>
A
Creates a new file containing standard output. If the specified file exists; it’s overwritten. No file descriptor necessary.
19
Q
> >
A
Appends standard output to the existing file. If the specified file doesn’t exist; it’s created. No file descriptor necessary.
20
Q
2>
A
Creates a new file containing standard error. If the specified file exists; it’s overwritten. File descriptor necessary.
21
Q
2»
A
Appends standard error to the existing file. If the specified file doesn’t exist; it’s created. File descriptor necessary.
22
Q
&>
A
Creates a new file containing both standard output and standard error. If the specified file exists; it’s overwritten. No file descriptors necessary.
23
Q
A
Sends the contents of the specified file to be used as standard input. No file descriptor necessary.
24
Q
<
A
Accepts text on the following lines as standard input. No file descriptor necessary.
25
<>
Causes the specified file to be used for both standard input and standard output. No file descriptor necessary.
26
COMMAND1 | COMMAND2
link stdout from COMMAND1 to stdin of COMMAND2
27
tee
display stdin on stdout and save it to the specified files
28
xargs [ options ] [ command [ initial-arguments ]]
run command once for every word passed to it on standard input
find / -user Christine | xargs -d "" \ n"" rm
29
`COMMAND`
a separate command whose results are substituted on the command line
rm ` find . / -user Christine `
30
$(COMMAND)
a separate command whose results are substituted on the command line
rm $(find ./ -user Christine)
31
cat
concatenate files and print on the standard output
32
tac
concatenate files and print on the standard output in reverse line order
33
join
For each pair of input lines with identical join fields; write a line to standard output. The default join field is the first; delimited by blanks.
Fields are typically space-separated entries on a line
34
paste
Write lines consisting of the sequentially corresponding lines from each FILE; separated by TABs; to standard output
35
expand
Convert tabs in each FILE to spaces; writing to standard output.
assumes a tab stop every eight characters
36
od
dump files in octal and other formats
37
sort
sort lines of text files
38
split
Output pieces of FILE to PREFIXaa; PREFIXab; ...; default size is 1000 lines; and default PREFIX is 'x'.
split -l 2 listing1.1.txt numbers
39
tr [ options ] SET1 [ SET2 ]
```
Translate; squeeze; and/or delete characters from standard input; writing to standard output
tr BCJ bc < listing1.1.txt
B is replaced with b
C is replaced with c
J is replaced with c
```
40
unexpand
unexpand - convert spaces to tabs
| defaults to 8
41
uniq
report or omit repeated lines
42
fmt
Reformat each paragraph in the FILE(s); writing to standard output.
(default of 75 columns)
43
nl
number lines of files (non empty)
| the similar to ""cat -b"" by default
44
pr
Paginate or columnate FILE(s) for printing
| defaults to 80 columns
45
head
Print the first 10 lines of each FILE to standard output. With more than one FILE; precede each with a header giving the file name.
46
tail
Print the last 10 lines of each FILE to standard output. With more than one FILE; precede each with a header giving the file name.
47
less
Less is a program similar to more (1); but it has many more features.
48
cut
Print selected parts of lines from each FILE to standard output.
49
wc
Print newline; word; and byte counts for each FILE; and a total line if more than one FILE is specified. A word is a non-zero-length sequence of characters delimited by white space.
50
grep
searches for PATTERN in each FILE
51
sed
stream editor for filtering and transforming text
sed [ options ] -f script-file [ input-file ]
sed [ options ] script-text [ input-file ]
52
rpm
RPM Package Manager
53
rpm2cpio
converts the .rpm file specified as a single argument to a cpio archive on standard out. If a '-' argument is given; an rpm stream is read from standard in.
54
cpio
copy files to and from archives
find ./my-work | cpio -o > /media/usb/my-work.cpio
cpio -i < /media/usb/my-work.cpio
55
yum
a repository based rpm manage
used by: Red Hat; CentOS; Fedora; and some other RPM-based distributions
not usd by: SUSE and Mandriva;
56
yumdownloader
yumdownloader is a program for downloading RPMs from Yum repositories
57
kyum
a gui frontend for yum
| also yumex
58
yumex
a gui frontend for yum
| also kyum
59
dpkg
debian's equivelant of rpm
60
dselect
a high-level interactive package browser. Using it; you can select packages to install on your system from the APT archives defined in /etc/apt/sources.list ; review the packages that are already installed on your system; uninstall packages; and upgrade packages.
61
apt-get
debian's equivelant of yum
62
apt-cache
apt-cache performs a variety of operations on APT's package cache. apt-cache does not manipulate the state of the system but does provide operations to search and generate interesting output from the package metadata. The metadata is acquired and updated via the 'update' command of e.g. apt-get; so that it can be outdated if the last update is too long ago; but in exchange apt-cache works independently of the availability of the configured sources (e.g. offline).
63
aptitude
a text based debian package manager with an optional interactive mode that is similar to dselect
64
synaptic
a X gui program similar to dselect or aptitude
65
dpkg-reconfigure
reconfigures packages after they have already been installed. Pass it the names of a package or packages to reconfigure. It will ask configuration questions; much like when the package was first installed.
66
alien
converts between Red Hat rpm; Debian deb; Stampede slp; Slackware tgz; Solaris pkg; and tarballs
requires that you have appropriate package manager software installed—for instance; both RPM and Debian—to convert between these formats
When converting from a tarball; alien copies the files directly as they had been in the tarball; so alien works only if the original tarball has files that should be installed off the root ( / ) directory of the system
67
$LD_LIBRARY_PATH
This environment variable specifies additional directories the system is to search for libraries
Does not require ldconfig for changes to take effect
68
ldd
prints the shared objects (shared libraries) required by each program or shared object specified on the command line.
69
ldconfig
usually called without any options
updates caches and links used by the system for locating libraries—that is; it reads /etc/ld.so.conf and implements any changes in that file or in the directories to which it refers
70
uname
Print certain system information. With no OPTION; same as -s
| node(host) name; kernel name; kernel version; kernel release; machine; processor; hardware platform; os name
71
ps
ps displays information about a selection of the active processes.
72
top
provides a dynamic real-time view of a running system
73
free
displays the total amount of free and used physical and swap memory in the system; as well as the buffers and caches used by the kernel. The information is gathered by parsing /proc/meminfo. T
74
uptime
gives a one line display of the following information. The current time; how long the system has been running; how many users are currently logged on; and the system load averages for the past 1; 5; and 15 minutes
the same information displayed in the header of w
75
jobs
displays minimal information about the processes associated with the current session
76
pgrep
looks through the currently running processes and lists the process IDs which match the selection criteria to stdout.
pgrep -u root cron
77
bg
move the specified job to the background, or start the first background process if it is stopped
78
fg
bring the specified job to the foreground
79
nice
Run COMMAND with an adjusted niceness (defaults to 10); which affects process scheduling. With no COMMAND; print the current niceness.
80
renice
renice alters the scheduling priority of one or more running processes.
renice 7 16580 -u pdavison tbaker
81
kill
send a signal to a process
The default signal for kill is TERM.
used to stop programs
82
nohup
Run COMMAND; ignoring hangup signals
83
killall
kill processes by name
| killall vi
84
pkill
allows you to kill one or more processes based on usernames; user IDs; group IDs; and other features as well as using a matching regular expression
85
setpci
a utility for querying and configuring PCI devices.
86
lspci
utility for displaying information about PCI buses in the system and devices connected to them
87
lsmod
a trivial program which nicely formats the contents of the /proc/modules (kernel modules)
88
insmod
```
a trivial program to insert a module into the kernel. Most users will want to use modprobe(8) instead; which is more clever and can handle module dependencies.
e.g. insmod /lib/modules/3.16.6/kernel/drivers/bluetooth/bluetooth.ko
```
89
modprobe
```
intelligently adds or removes a module from the Linux kernel
e.g. modprobe bluetooth
```
90
rmmod
a trivial program to remove a module (when module unloading support is provided) from the kernel. Most users will want to use modprobe(8) with the -r option instead.
91
lsusb
a utility for displaying information about USB buses in the system and the devices connected to them
92
pvcreate
initialize a disk or partition for use by LVM
93
vgcreate
create a volume group (for LVM)
94
lvcreate
create a logical volume in an existing volume group (for LVM)
95
lvscan
scan (all disks) for Logical Volumes (for LVM)
96
fdisk
a dialog-driven program for creation and manipulation of partition tables. It understands GPT; MBR; Sun; SGI and BSD partition tables.
the book says this tool can't do GPT even though it can
e.g. fdisk /dev/hda
97
gdisk
GPT fdisk (aka gdisk) is a text-mode menu-driven program for creation and manipulation of partition tables
98
mkfs
build a Linux filesystem
deprecated in favour of filesystem specific mkfs. utils
mkfs -t ext3 /dev/sda6
99
mkswap
sets up a Linux swap area on a device or in a file
| mkswap /dev/sda7
100
swapon
used to specify devices on which paging and swapping are to take place
/dev/sda7
101
dumpe2fs
dump ext2/ext3/ext4 filesystem information
| prints the super block and blocks group information for the filesystem present on device
102
xfs_info
like dumpe2fs but for xfs; displays filesystem info
103
xfs_metadump
copies the filesystem's metadata (filenames; file sizes; and so on) to a file
104
tune2fs
enables you to change many of the filesystem parameters that are reported by dumpe2fs
adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems
105
fsck
check and repair a Linux filesystem
106
xfs_admin
xfs equivelant to tune2fs
| xfs_admin -L av_data /dev/sda7
107
blkid
display the label and UUID of any partition's filesystem
108
debugfs
provides the abilities of dumpe2fs ; tune2fs ; and many of Linux's normal file-manipulation tools all rolled into one
an interactive file system debugger. It can be used to examine and change the state of an ext2; ext3; or ext4 file system
e.g. debugfs /dev/sda11
109
xfs_db
xfs equivelant to debugfs; only for experts
110
df
report file system disk space usage
111
du
estimate file space usage
112
mount
mount a filesystem
| mount /dev/sdb7 /mnt/shared
113
umount
unmount file systems
114
ls
list directory contents
115
cp
make a copy
116
mv
move (rename) files
117
rm
remove files or directories
118
touch
Update the access and modification times of each FILE to the current time
119
tar
an archiving utility
120
gzip
compress or expand files; oldest least compression
121
bzip2
a block-sorting file compressor; improved over gzip
122
xz
Compress or decompress .xz and .lzma files newest and best compression compared to gzip and bzip2
123
dd
Copy a file; converting and formatting according to the operands.
very low level
124
ln
make links between files
ln [options] source link
you can't make hard links to directories
125
mkdir
make directories
126
rmdir
remove empty directories
127
chown
change file owner and group
chown [ options ] [ newowner ][: newgroup ] filenames
eg. chown sally:skyhook forward.odt
Ordinary users may use chown to change the group of files that they own; provided that the users belong to the target group
128
chmod
change file mode bits (permissions)
| chmod [ options ] [ mode [; mode... ]] filename...
129
umask
sets the bits that will be removed from 777 for directories and 666 for files when a new file/directory is created
130
newgrp
set the users default group
| newgrp mygroup
131
chattr
change file attributes on a Linux file system
132
lsattr
display file attributes
133
quotaon
turn on disk quotas
134
quotaoff
turn off disk quotas
135
quotacheck
surveys the filesystem needing quotas and builds current disk usage data records.
e.g. create needed files and check the user quota on home: quotacheck -cu /home
136
edquota
open a text editor to edit quotas
137
repquota
summarizes the quota information about the filesystem you specify or on all filesystems if you pass it the -a option
138
quota
display disk usage and limits
139
find
search for files in a directory hierarchy
140
locate
reads one or more databases prepared by updatedb(8) and writes file names matching at least one of the PATTERNs
141
updatedb
creates or updates a database used by locate(1)
142
whereis
searches for files in a restricted set of locations; such as standard binary file directories; library directories; and man page directories.
143
which
searches your path for the command that you type and lists the complete path to the first match it finds
144
grub-install
```
installs grub legacy
grub-install /dev/sda
grub-install '(hd0)'
install to bootsector instead of MBR:
/dev/sda1 or (hd0;0)
```
145
efibootmgr
manipulate the EFI Boot Manager
| efibootmgr -c -l \\EFI\\redhat\\grub.efi -L GRUB
146
update-grub
```
apply changes from
/etc/default/grub
and
/etc/grub.d/
to
/boot/grub/grub.cfg
or grub-mkconfig
some versions output to stdio; if so redirect them to the file
/boot/grub/grub.cfg
```
147
dmesg
```
print or control the kernel ring buffer
kernel and module log messages
sometimes it's in /var/log/dmesg
```
148
chkconfig
(SysV) updates and queries runlevel information for system services
149
runlevel
returns the previous and current runlevel
150
init
reread the /etc/inittab file and change runlevels
151
telinit
just like init; but telinit [qQ] will re-read the /etc/inittab
152
shutdown
shutdown the machine
| shutdown -h +15 ""system going down for maintenance""
153
halt
halt the machine
154
reboot
reboot the machine
155
poweroff
poweroff the machine
156
systemctl
Control the systemd system and service manager
157
journalctl
Query the systemd journal
158
pwd
print the working directory
159
echo STRING
display text from stdin
160
time COMMAND
times how long COMMAND takes to execute
| Three times are displayed: totalexecution time (aka real time); user CPU time; and system CPU time
161
set
displays a wide variety of options relating to bash shell operation
These options are formatted much like environment variables; but they aren't the same things. You can pass various options to set to have it affect a wide range of shell operations.
162
exit
terminates any shell
Login shells are shell programs that are launched automatically when you initiate a text-mode login as opposed to those that run in xterm windows or other terminal emulators
163
logout
terminates only login shells
Login shells are shell programs that are launched automatically when you initiate a text-mode login as opposed to those that run in xterm windows or other terminal emulators
164
type COMMAND
tells you how a command you enter will be interpreted—as a built-in command; an external command; an alias; and so on
165
history
displays all of the commands in the history
| typically the latest 500 commands
166
!!
display and execute the last command in your shell history
167
!NUMBER
execute command NUMBER from the history
168
$PATH
a directory list to search when you're entering command or program names
169
env
display environment variables
170
unset VARNAME
unset an environment variable
171
$PS1
the shell prompt
172
man COMMAND
display the manual for COMMAND
173
info COMMAND
hypertext formatted manual
174
help COMMAND
a built in manual for built in commands
175
>
Creates a new file containing standard output. If the specified file exists; it's overwritten. No file descriptor necessary.
176
>>
Appends standard output to the existing file. If the specified file doesn't exist; it's created. No file descriptor necessary.
177
2>
Creates a new file containing standard error. If the specified file exists; it's overwritten. File descriptor necessary.
178
2>>
Appends standard error to the existing file. If the specified file doesn't exist; it's created. File descriptor necessary.
179
&>
Creates a new file containing both standard output and standard error. If the specified file exists; it's overwritten. No file descriptors necessary.
180
Sends the contents of the specified file to be used as standard input. No file descriptor necessary.
181
<
Accepts text on the following lines as standard input. No file descriptor necessary.
182
<>
Causes the specified file to be used for both standard input and standard output. No file descriptor necessary.
183
COMMAND1 | COMMAND2
link stdout from COMMAND1 to stdin of COMMAND2
184
tee
display stdin on stdout and save it to the specified files
185
xargs [ options ] [ command [ initial-arguments ]]
run command once for every word passed to it on standard input
find / -user Christine | xargs -d "" \ n"" rm
186
`COMMAND`
a separate command whose results are substituted on the command line
rm ` find . / -user Christine `
187
$(COMMAND)
a separate command whose results are substituted on the command line
rm $(find ./ -user Christine)
188
cat
concatenate files and print on the standard output
189
tac
concatenate files and print on the standard output in reverse line order
190
join
For each pair of input lines with identical join fields; write a line to standard output. The default join field is the first; delimited by blanks.
Fields are typically space-separated entries on a line
191
paste
Write lines consisting of the sequentially corresponding lines from each FILE; separated by TABs; to standard output
192
expand
Convert tabs in each FILE to spaces; writing to standard output.
assumes a tab stop every eight characters
193
od
dump files in octal and other formats
194
sort
sort lines of text files
195
split
Output pieces of FILE to PREFIXaa; PREFIXab; ...; default size is 1000 lines; and default PREFIX is 'x'.
split -l 2 listing1.1.txt numbers
196
tr [ options ] SET1 [ SET2 ]
```
Translate; squeeze; and/or delete characters from standard input; writing to standard output
tr BCJ bc < listing1.1.txt
B is replaced with b
C is replaced with c
J is replaced with c
```
197
unexpand
unexpand - convert spaces to tabs
| defaults to 8
198
uniq
report or omit repeated lines
199
fmt
Reformat each paragraph in the FILE(s); writing to standard output.
(default of 75 columns)
200
nl
number lines of files (non empty)
| the similar to ""cat -b"" by default
201
pr
Paginate or columnate FILE(s) for printing
| defaults to 80 columns
202
head
Print the first 10 lines of each FILE to standard output. With more than one FILE; precede each with a header giving the file name.
203
tail
Print the last 10 lines of each FILE to standard output. With more than one FILE; precede each with a header giving the file name.
204
less
Less is a program similar to more (1); but it has many more features.
205
cut
Print selected parts of lines from each FILE to standard output.
206
wc
Print newline; word; and byte counts for each FILE; and a total line if more than one FILE is specified. A word is a non-zero-length sequence of characters delimited by white space.
207
grep
searches for PATTERN in each FILE
208
sed
stream editor for filtering and transforming text
sed [ options ] -f script-file [ input-file ]
sed [ options ] script-text [ input-file ]
209
rpm
RPM Package Manager
210
rpm2cpio
converts the .rpm file specified as a single argument to a cpio archive on standard out. If a '-' argument is given; an rpm stream is read from standard in.
211
cpio
copy files to and from archives
find ./my-work | cpio -o > /media/usb/my-work.cpio
cpio -i < /media/usb/my-work.cpio
212
yum
a repository based rpm manage
used by: Red Hat; CentOS; Fedora; and some other RPM-based distributions
not usd by: SUSE and Mandriva;
213
yumdownloader
yumdownloader is a program for downloading RPMs from Yum repositories
214
kyum
a gui frontend for yum
| also yumex
215
yumex
a gui frontend for yum
| also kyum
216
dpkg
debian's equivelant of rpm
217
dselect
a high-level interactive package browser. Using it; you can select packages to install on your system from the APT archives defined in /etc/apt/sources.list ; review the packages that are already installed on your system; uninstall packages; and upgrade packages.
218
apt-get
debian's equivelant of yum
219
apt-cache
apt-cache performs a variety of operations on APT's package cache. apt-cache does not manipulate the state of the system but does provide operations to search and generate interesting output from the package metadata. The metadata is acquired and updated via the 'update' command of e.g. apt-get; so that it can be outdated if the last update is too long ago; but in exchange apt-cache works independently of the availability of the configured sources (e.g. offline).
220
aptitude
a text based debian package manager with an optional interactive mode that is similar to dselect
221
synaptic
a X gui program similar to dselect or aptitude
222
dpkg-reconfigure
reconfigures packages after they have already been installed. Pass it the names of a package or packages to reconfigure. It will ask configuration questions; much like when the package was first installed.
223
alien
converts between Red Hat rpm; Debian deb; Stampede slp; Slackware tgz; Solaris pkg; and tarballs
requires that you have appropriate package manager software installed—for instance; both RPM and Debian—to convert between these formats
When converting from a tarball; alien copies the files directly as they had been in the tarball; so alien works only if the original tarball has files that should be installed off the root ( / ) directory of the system
224
$LD_LIBRARY_PATH
This environment variable specifies additional directories the system is to search for libraries
Does not require ldconfig for changes to take effect
225
ldd
prints the shared objects (shared libraries) required by each program or shared object specified on the command line.
226
ldconfig
usually called without any options
updates caches and links used by the system for locating libraries—that is; it reads /etc/ld.so.conf and implements any changes in that file or in the directories to which it refers
227
uname
Print certain system information. With no OPTION; same as -s
| node(host) name; kernel name; kernel version; kernel release; machine; processor; hardware platform; os name
228
ps
ps displays information about a selection of the active processes.
229
top
provides a dynamic real-time view of a running system
230
free
displays the total amount of free and used physical and swap memory in the system; as well as the buffers and caches used by the kernel. The information is gathered by parsing /proc/meminfo. T
231
uptime
gives a one line display of the following information. The current time; how long the system has been running; how many users are currently logged on; and the system load averages for the past 1; 5; and 15 minutes
the same information displayed in the header of w
232
jobs
displays minimal information about the processes associated with the current session
233
pgrep
looks through the currently running processes and lists the process IDs which match the selection criteria to stdout.
pgrep -u root cron
234
bg
move the specified job to the background, or start the first background process if it is stopped
235
fg
bring the specified job to the foreground
236
nice
Run COMMAND with an adjusted niceness (defaults to 10); which affects process scheduling. With no COMMAND; print the current niceness.
237
renice
renice alters the scheduling priority of one or more running processes.
renice 7 16580 -u pdavison tbaker
238
kill
send a signal to a process
The default signal for kill is TERM.
used to stop programs
239
nohup
Run COMMAND; ignoring hangup signals
240
killall
kill processes by name
| killall vi
241
pkill
allows you to kill one or more processes based on usernames; user IDs; group IDs; and other features as well as using a matching regular expression
242
setpci
a utility for querying and configuring PCI devices.
243
lspci
utility for displaying information about PCI buses in the system and devices connected to them
244
lsmod
a trivial program which nicely formats the contents of the /proc/modules (kernel modules)
245
insmod
```
a trivial program to insert a module into the kernel. Most users will want to use modprobe(8) instead; which is more clever and can handle module dependencies.
e.g. insmod /lib/modules/3.16.6/kernel/drivers/bluetooth/bluetooth.ko
```
246
modprobe
```
intelligently adds or removes a module from the Linux kernel
e.g. modprobe bluetooth
```
247
rmmod
a trivial program to remove a module (when module unloading support is provided) from the kernel. Most users will want to use modprobe(8) with the -r option instead.
248
lsusb
a utility for displaying information about USB buses in the system and the devices connected to them
249
pvcreate
initialize a disk or partition for use by LVM
250
vgcreate
create a volume group (for LVM)
251
lvcreate
create a logical volume in an existing volume group (for LVM)
252
lvscan
scan (all disks) for Logical Volumes (for LVM)
253
fdisk
a dialog-driven program for creation and manipulation of partition tables. It understands GPT; MBR; Sun; SGI and BSD partition tables.
the book says this tool can't do GPT even though it can
e.g. fdisk /dev/hda
254
gdisk
GPT fdisk (aka gdisk) is a text-mode menu-driven program for creation and manipulation of partition tables
255
mkfs
build a Linux filesystem
deprecated in favour of filesystem specific mkfs. utils
mkfs -t ext3 /dev/sda6
256
mkswap
sets up a Linux swap area on a device or in a file
| mkswap /dev/sda7
257
swapon
used to specify devices on which paging and swapping are to take place
/dev/sda7
258
dumpe2fs
dump ext2/ext3/ext4 filesystem information
| prints the super block and blocks group information for the filesystem present on device
259
xfs_info
like dumpe2fs but for xfs; displays filesystem info
260
xfs_metadump
copies the filesystem's metadata (filenames; file sizes; and so on) to a file
261
tune2fs
enables you to change many of the filesystem parameters that are reported by dumpe2fs
adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems
262
fsck
check and repair a Linux filesystem
263
xfs_admin
xfs equivelant to tune2fs
| xfs_admin -L av_data /dev/sda7
264
blkid
display the label and UUID of any partition's filesystem
265
debugfs
provides the abilities of dumpe2fs ; tune2fs ; and many of Linux's normal file-manipulation tools all rolled into one
an interactive file system debugger. It can be used to examine and change the state of an ext2; ext3; or ext4 file system
e.g. debugfs /dev/sda11
266
xfs_db
xfs equivelant to debugfs; only for experts
267
df
report file system disk space usage
268
du
estimate file space usage
269
mount
mount a filesystem
| mount /dev/sdb7 /mnt/shared
270
umount
unmount file systems
271
ls
list directory contents
272
cp
make a copy
273
mv
move (rename) files
274
rm
remove files or directories
275
touch
Update the access and modification times of each FILE to the current time
276
tar
an archiving utility
277
gzip
compress or expand files; oldest least compression
278
bzip2
a block-sorting file compressor; improved over gzip
279
xz
Compress or decompress .xz and .lzma files newest and best compression compared to gzip and bzip2
280
dd
Copy a file; converting and formatting according to the operands.
very low level
281
ln
make links between files
ln [options] source link
you can't make hard links to directories
282
mkdir
make directories
283
rmdir
remove empty directories
284
chown
change file owner and group
chown [ options ] [ newowner ][: newgroup ] filenames
eg. chown sally:skyhook forward.odt
Ordinary users may use chown to change the group of files that they own; provided that the users belong to the target group
285
chmod
change file mode bits (permissions)
| chmod [ options ] [ mode [; mode... ]] filename...
286
umask
sets the bits that will be removed from 777 for directories and 666 for files when a new file/directory is created
287
newgrp
set the users default group
| newgrp mygroup
288
chattr
change file attributes on a Linux file system
289
lsattr
display file attributes
290
quotaon
turn on disk quotas
291
quotaoff
turn off disk quotas
292
quotacheck
surveys the filesystem needing quotas and builds current disk usage data records.
e.g. create needed files and check the user quota on home: quotacheck -cu /home
293
edquota
open a text editor to edit quotas
294
repquota
summarizes the quota information about the filesystem you specify or on all filesystems if you pass it the -a option
295
quota
display disk usage and limits
296
find
search for files in a directory hierarchy
297
locate
reads one or more databases prepared by updatedb(8) and writes file names matching at least one of the PATTERNs
298
updatedb
creates or updates a database used by locate(1)
299
whereis
searches for files in a restricted set of locations; such as standard binary file directories; library directories; and man page directories.
300
which
searches your path for the command that you type and lists the complete path to the first match it finds
301
grub-install
```
installs grub legacy
grub-install /dev/sda
grub-install '(hd0)'
install to bootsector instead of MBR:
/dev/sda1 or (hd0;0)
```
302
efibootmgr
manipulate the EFI Boot Manager
| efibootmgr -c -l \\EFI\\redhat\\grub.efi -L GRUB
303
update-grub
```
apply changes from
/etc/default/grub
and
/etc/grub.d/
to
/boot/grub/grub.cfg
or grub-mkconfig
some versions output to stdio; if so redirect them to the file
/boot/grub/grub.cfg
```
304
dmesg
```
print or control the kernel ring buffer
kernel and module log messages
sometimes it's in /var/log/dmesg
```
305
chkconfig
(SysV) updates and queries runlevel information for system services
306
runlevel
returns the previous and current runlevel
307
init
reread the /etc/inittab file and change runlevels
308
telinit
just like init; but telinit [qQ] will re-read the /etc/inittab
309
shutdown
shutdown the machine
| shutdown -h +15 ""system going down for maintenance""
310
halt
halt the machine
311
reboot
reboot the machine
312
poweroff
poweroff the machine
313
systemctl
Control the systemd system and service manager
314
journalctl
Query the systemd journal
