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