#LinuxClient

Command	Description
ex	execute
ps	see active operations
kill	close apps
grep	to see active processes
-9	to force closing
dash	text editor
exit	to leave
pwd	show the current directory
history	all the commands entered
ctrl + r	to reverse search the commands entered in the history
-c	to clear
history -c	to clear the history
ls -a	list all +hidden files
ls -ar	list all files read-only
ctrl + l	clear the screen
ctrl + w	clear the last word
ctrl + d	to close the terminal
shift + Page Up / Down	to go up / down in the page
ctrl + a / ctrl + e	go to the beginning of the line / go to end
ctrl + y	undo the last action
tree	to see directories in a more organized manner
ls -alR	see all the repertories
-h	humanized version, like changing bytes to gigabytes etc
which firefox	to find the directory of firefox
firefox &	to start firefox and continue working on the terminal not being related to the app launched (firefox in this case)
kill 56846 (process number of firefox)	to close firefox by the process number we acquire with the previous command
cat	display the contents of a document
grep -w war file_name	search war in file_name document, for example search for root in auth.log
| more	to see only the content filling the page
| less	to see the content and being able to go up and down
d / b (while in less)	go / go back 10 lines
y (while in less)	go down 1 line
/"search_term" (while in less)	to search certain terms in less we click / and write the term
n (while in less and searching a term)	to display the next searched term line
/term1.*term2 (while in search in less)	to search 2 different terms in a line
head -n 3 syslog	see the first 3 lines of syslog
tail syslog	see the last 10 lines of syslog
tail -f syslog	follow the current activities and log them
sudo dhclient	ipconfig /release and /renew and does DHCP DORA, Discover, Offer, Request, Acknowledge
	![[Pasted image 20240320102340.png]]
-r	to force, reload
cd + enter	cd and space and enter goes to user's home
touch	to open a file, if the file doesn't exist, it creates it
-F	see files in an organized manner
mkdir	create a directory
rmdir	remove a directory
mkdir tt/tt1/tt2	to create subdirectories
cp	to copy files and directories
mv	move files and directories or change/replace the file name
cp file filecopy	to copy 'file' as 'filecopy' name
cp file myfile/	to copy 'file' inside the myfile directory
-v	to see the confirmation of the action done
rm -r myfiles/testfiles	to remove directory (if it's empty)
ln	to link files, creates a second file linked to the first one
nano	for text editor
-i	to see the inode (which number does the file has in the harddisk)
cat	view the content of the file
ln -s	to create an alias / shortcut
-ali	see details with inode, all, writing rights
sudo su	to pass to the root account and stay there, gives # at the end
neofetch	to see all details of the system like version info, should apt install it first
ls -al	view rights, users, groups, directories
cd ../..	to go to the first directory in the path
ps guaxf	to see active services, or kill them
uname -r	to see the current linux kernel version

User accounts

Command	Description
adduser	creates a new user in the system
sudo su	pass to the root account and stay
passwd patrick	change the password of patrick
deluser	delete a user, but doesn't delete the group
cat /etc/group-	to see the user groups
nano /etc/group-	to delete the group of the user (in our case; patrick)
deluser --remove-home patrick	to delete user completely and it's files/directory
usermod	modify a user
addgroup	add a group
usermod -g amis admin3(username)	change the group of a user
usermod -aG amis,paris,tssr patrick	add patrick to these 3 groups
chown	change the owner (user level) of a file
chg	to change password or group
chgrp	change the group
sudo chown admin3:admin3 fichier1.txt	change owner and the group of the fichier1.txt to be the admin3
-R	heritage, all the sub-directories obtain the same rights
sudo chown -R admin3:admin3 /home/patrick/	change all the rights of the patrick user's file to admin3. in this case patrick cannot access to his account
chmod 644 fichier1.txt	change the rights of fichier1.txt to be -rw-r--r--
chmod g+w fichier1.txt	change the group rights of the fichier1.txt , add write right
chmod o-r fichier1.txt	change the other's rights of the fichier1.txt, remove the writing right
chmod u+x fichier1.txt	when we give x to a file, we make it executable. when we edit it to be a script
./fichier1.txt	to execute the script
echo $HOME	show the directory of the home file
sudo apt clean	cleans the system, cleans the unnecessary small files
sudo apt purge	to force and clean everything that might have stayed from a program
locate	finds the location of a file, doesn't work with * **. ** *, should update, doesn't work very good, find is way better
FIND
find	powerful tool to search.
find -name "firefox"	to search only the files that has this name
find /var/log/ -name "syslog"	find in a certain directory
sudo find / -name "syslog"	searches in the root
find -name "*.txt" -atime -7	atime for accessing time stamp, -7 for the last 7 days
sudo find /var/log "syslog" -type d	type d to list only directories
find . -name "*.txt" -printf "%p - %u\n"	. to start from the current directory, printf for the results, %u for the user who created it, n for the name of the user
sudo find / -name "*.tmp" -delete	delete all the files with this name *.tmp
find -name "*.txt" -exec chmod 600 {} \;	find all these files and chmod their their rights
GREP
grep	for filtering files, shows the words/word-groups even inside the files as lines
grep alias .bashrc	colors the alias lines in all the .bashrc files
grep -i -n alias .bashrc	shows the line numbers and doesn't take into account minuscule or majuscule letters
SORT
sort names.txt	sorts the content of the file, doesn't modify it, just shows !!
sort -o noms_tries.txt noms.txt	-o for output, to modify it
sort -r names.txt	-r for inversing the list
sort -R names.txt	-R for shuffling the list
sort -n numbers.txt	-n for sorting the numbers in increasing order
---
wc names.txt	word count for the file. 8 8 64 names.txt first ; number for lines, second ; number of words, third ; number of letters.
uniq doublons.txt	display the result as all the duplicates deleted
uniq doublons.txt sans_doublons.txt	creates a new file without the duplicates
uniq -c doublons.txt	-c counts the duplicate numbers
uniq -d doublons.txt	shows only the duplicated values once
cut -c 2-5 names.txt	shows only between the 2nd and 5th letters in the value
cut 1er-lettre	only shows the first letter of each value
cut -d , -f 1 notes.csv	-d to indicate the separator ( , in our case), -f to indicate the number of the column
libreoffice --calc notes.csv	to see the columns in the calculator or excel
cut -d , -f 2-4 notes.csv	shows the results of the values between 2nd and 4th columns
cut -d , -f 3- notes.csv	shows the results of the values starting from the 3rd column and anything after
cut -d , -f 1 notes.csv > eleves.txt	create a new .txt with the first column's values, override or create
cut -d , -f 1 notes.csv >> eleves.txt	add the values at the end of the values if there are 2 >>.

An example script we have made; ![[Pasted image 20240320163546.png]]

In the list first column is users, second is groups ![[users and groups in linux 2.png]]

Zip & RAR

Command	Description
tar -cvf nom_archive.tar nom_dossier/	create a .tar with a certain file/directory -c : to create a tar archive -v : to display the details of the action -f : to get the archive at one piece in a file
tar -tf images.tar	to see the contents of the file
tar -rvf images.tar fichier_supplementaire.jpg	add an extra file inside the archive

System Monitoring & Surveillance

Command	Description
ps -ef	to see the active processes
kill -9 (process number)	stop the process directly
firefox&	see the process number of firefox
killall firefox-bin	to kill the process with the name
ps -e | firefox	to see the process name of firefox
sudo halt	to stop the system
sudo reboot	to reboot the system