Cheat Sheet
November 20, 2022 - 17:54:44 —
CaylakPenguen
Cheat Sheet
If you can't remember, write it down :)
# MySQL
# Admin Commands
# Cool Commands
# SSH Tunnel
# GPG
# vim
# firewalld
# tmux
MySQL
User administration
Create user, and grant permissions to database.
% Can be used as a wildcard to allow all hosts to connect.
GRANT ALL PRIVILEGES ON Databasename.* to username@"localhost"
IDENTIFIED BY 'mysecretpassword';
FLUSH PRIVILEGES;
Search for a string replace, does not replace, only show search result.
SELECT REPLACE( '', 'u', 'span class="underline"' ) FROM content;
Search and replace a string in MySQL.
UPDATE tblname SET fieldname = replace(fieldname,'orgiginal text','replacement text');
Backup and Restore
Restore a full dump, with all databases
mysql -u [user] -p < mysqlDump.gz
Restore a full gz dump, with all databases
pigz -dc mysqlDump.gz |mysql -u [user] -p
Restore a dump of a single database. Database would likely need to be precreated
mysql -u [user] -p [db_name_to_restore_to] < mysqlDump.gz
Restore a gz dump of a single database. Database would likely need to be precreated
pigz -dc mysqlDump.gz |mysql [db_name_to_restore_to] -u [user] -p
Useful commands
Show listening ports and programs attached
netstat -lnp -A inet
Check webserver certificate
openssl s_client -connect exmaple.com:443 |openssl x509 -text
And see the date only
openssl s_client -connect exmaple.com:443 |openssl x509 -noout -dates
Cool commands
awk
$0 full line, nomatter delimiter
Print lines starting with #, and printing column 5 and 6 on all others
cat testtext.txt |awk '{if($1 =="#"){print $0} else {print $5,$6}}'
print first 4 chars
| awk '{ print substr($1,0,3) }'
print last 4 chars
| awk '{ print substr($1,length($1)-4,length($1)) }'
print if $1 larger or equels 666
| awk '$1>=666{print $1}'
# larger than and less than
|awk -F',' '$2>=1607 && $2<=1612 {print $2}'
do an regex match and print
cat feeds/myfile.csv |awk -F',' '{ if($3 ~ /^36/) print $3}'
#do an regex !notmatch and print
cat feeds/myfile.csv |awk -F',' '{ if($3 !~ /^7/) print $3}'
#regex field seperator (space and ? )
awk -F' |?'
SSH Tunnel
ssh user@remotehost -L localport:remoteip:destinationport
ssh nsroot@server -L 3008:192.168.100.150:3008 -N -v
GPG
Generating gpg keypair
gpg --gen-key
# or, which allows more options
gpg --full-gen-key
List keys:
gpg --list-keys
List the secret keys
gpg --list-secret-keys
Import key:
gpg --import
Export public key:
gpg --export --armor >mypublicfilename.asc
Export public key:
gpg --export-secret-key --armor "User Name" > >myprivatekeyfilename.asc
Delete public key:
gpg --delete-key ""
Export private key:
gpg --delete-secret-key ""
Encrypt:
Decrypt:
If there are multiple keys, it will automatically choose the correct one. If there are not correct keys available, it will exist with an error.
gpg -d
vim
Open files
:Ex - open filexplorer in current window
:Vex - opens a new vertical window
:Sex - open a new horizinal window
% - Create a new file, in explorer mode.
Movement
:Nn - move to line number Nn
$ - move to end of line
Marking text
v - visual mode
aw - mark word
Marked edits
:s/oldtext/newtext/g - Will search the marked text, and replace
ctrl-v,mark the text, then shift+i to insert at cursor only, escape finalize edit - Insert text at multiple lines
Editing
yy - copy line
2yy - copy 6 lines
yw - copy word
y$ - copy to end of line
dd - delete/cut line
dw - delete/cut word
d$ - delete/cut to end of line
p - put "clipboard" after "cursor"
P - put "clipboard" before "cursor"
u - undo
o - insert below
ci' - delete word inside '', and insert go to insert mode.
shift+A - insert end of line
ctrl+shift+A - will add +1 to number at cursor.
. - redo last action
Search / Replace
Delete lines starting with *
:g/^\*/d
Multiple windows/files
ctrl+ws - split window
ctrl+ww - switch window
ctrl+wv - split window vertically
ctrl+wq - quit window
ctrl+wn - splut horizontal
Recording
q[x] - start recording, followed by a letter, example X
q - stop recording
@x - execute recording from register x
100@x - execute recording 100 times from register x
Other
:%s/^/newtext/ - will prepend 'newtext' on all lines
:%s/$/newtext/ - will append 'newtext' on all lines
firewalld
General info about firewalld
when using --permanent reload is required
when --permanent is not applied, it works instantly. If reload is ran, the rules will be whiped
Zones are at set of "predefines rules" which can be added to different interfaces.
Zones ONLY becomes active when there's an interface OR source ip addresses assigned to the zone.
Zones is added to interfaces. For example 'internal' is added to an internal interface where only LAN traffics passes.
Direct rules should be used as an last option resort, when add-service or add-rich-rule is not possible (man page refs) Ref: http://www.firewalld.org/documentation/man-pages/firewalld.zones.html
Zones are located in /usr/lib/firewalld/zones/ and/or /etc/firewalld/zones/
Man page reference tags
from firewalld-cmd --help
[P] = (--permanent)
[Z] = (--zone=)
List Rules for default zone
firewall-cmd --list-all
Get default zone
firewall-cmd --get-default-zone
Get active zones
firewall-cmd --get-active-zones
List information from an non default zone
firewall-cmd --info-zone=
List everything added for, or enabled from an non default zone
firewall-cmd --list-all --zone=
Set default zone
firewall-cmd --set-default-zone=drop
Create new zone
firewall-cmd --new-zone=test --permanent
firewall-cmd reload
firewall-cmd --zone=testzone --add-service=mysql
Delete an zone
firewall-cmd --delete-zone=bla --permanent
Get available services for an zone
firewall-cmd --get-services
List rich/direct/nat rules
firewall-cmd --list-rich-rules
firewall-cmd --direct --get-all-rules
#permanent direct rules
firewall-cmd --permanent --direct --get-all-rules
#permanent rich rules
firewall-cmd --permanent --list-rich-rules
Change zone on an interface
firewall-cmd --zone=block --change-interface=eth0
firewall-cmd --get-active-zones
Add port to default zone (RUNTIME only)
firewall-cmd --add-port=3306/tcp
#add multiple ports
firewall-cmd --add-port={3306/tcp,5000/tcp}
#port range
firewall-cmd --add-port=5000-5010/tcp
Add services to default zone
firewall-cmd --add-service={http,https} --permanent
Add source to an zone
This would allow all services from this IP which is in the "testzone"
firewall-cmd --zone=testzone --add-source=192.168.10.1 --permanent
delete port rules
Instead of add, remove should be used.
firewall-cmd --remove-port=3306/tcp
# delete rich rules (tip, get the full rule from firewall-cmd --list-rich-rules, and use exact this.
firewall-cmd --remove-rich-rule 'rule family="ipv4" source address="192.168.10.11/26" port port="1556" protocol="tcp" accept'
# remove direct rules
firewall-cmd --permanent --direct --remove-rule ipv4 filter OUTPUT 1 -j DROP
#port forwarding,locally
firewall-cmd --add-forward-port=port=8080:proto=tcp:toport=80
#port forwrding, "external"
firewall-cmd --add-forward-port=port=8080:proto=tcp:toport=80:toaddr=xxx.xxx.xxx.xxx
Save running conf
firewall-cmd --runtime-to-permanent
Generating specific source rules, rich-rule
#accept
firewall-cmd --add-rich-rule='rule family="ipv4" source address="xxx.xxx.xxx.xxx" accept'
#drop
firewall-cmd --add-rich-rule='rule family="ipv4" source address="xxx.xxx.xxx.xxx" drop/reject'
Add rich-rule to zone
firewall-cmd --add-rich-rule='rule family="ipv4" source address="192.168.10.11/32" port protocol="tcp" port=10050 accept' --zone=internal --permanent
Creating NAT direct rules
For example for loadbalancers.org, VIPs. We need to use direct rules here, since rich-rules cannot be used.
firewall-cmd --permanent --direct --add-rule ipv4 nat PREROUTING 0 -p tcp -m tcp --dport 8080 -d 192.168.10.100/32 -j REDIRECT
# redirect outgoing traffic to 192.168.10.100:8080 to 192.168.10.10:8080
firewall-cmd --permanent --direct --add-rule ipv4 nat OUTPUT 0 -p tcp -d 192.168.10.100/32 --dport 8080 -j DNAT --to-destination 192.168.10.10:8080
Drop outgoing traffic
firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -p tcp -m tcp --dport=45688/ -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -p tcp -m tcp --dport=23364/ -j DROP
firewall-cmd --permanent --direct --add-rule ipv4 filter OUTPUT 0 -p tcp -m tcp --dport=3306/ -j DROP
Lockdown server quickly
/etc/firewalld/firewalld.conf Lockdown=yes
tmux
Panes:
Split pane vertical: ctrl+b %
Split pane horizontal: ctrl+b "
Switch pane: ctrl+b o
Switch pane: ctrl+b ARROW-KEYSv
show pane numbers: ctrl-b q
change layout: ctrl-b SPACE
resize pane(s): HOLD ctrl+b ARROW-KEYS
zoom/fullscreen: ctrl-b z
swap current pane with previous: ctrl+b {
swap current pane with next: ctrl+b }
kill pane: ctrl+b x
Scroll: ctrl+b pgup/pgdown, will enable scrolling
Basics:
Detach: ctrl+b d
Show seesions: tmux ls
attach: tmux attach / tmux attach -t
Other:
show shortcuts: ctrl+b ?
Tags: cheatsheet