linux-commands.txt

https://linuxsurvival.com/linux-tutorial-introduction/

Linux is case-sensitive

Fundamentals of file manipulation
---------------------------------

ls //list the contents of a directory.
ls -la
ls -l // each file will be listed on a separate line in long format
    ls * // '*' matches any number of characters. 
    ls *ing
    ls sp??t // '?' matches exactly one character.

-rw-r--r-- 1 natat 197609  88832 Feb 11 16:52 6kn.gif
  -----  -----  -----
- r w x  r w x  r w x
d owner  group  other
The 'r' means you can "read" the file's contents.
The 'w' means you can "write", or modify, the file's contents.
The 'x' means you can "execute" the file. 

more cobras //

mkdir New_Dir_Name // create new directory

mv file_name to_place // moving file from one place to other
mv old_file_name new_file_name // renaming file

cd uri // change directory
cd .. // move to parent directory
cd ~ // go to your home directory
cd // go to your home directory, by default

"." // current directory 

pwd // print working directory

cp from_where to_where // copy from - to

rm reptiles/cobras // remove file
rmdir reptiles // remove empty directory
rm -r stocks // remove a directory called "stocks" and all of its subdirectories and files

chmod // change mode, The first argument is 'u', 'g', 'o'
  chmod ugo-rwx gorillas
  chmod u+x gorillas

groups //shows groups you are in

cp ~/jokes /tmp // copy file jokes from home ditectory to /tmp
    '~' home user directory
    '~UserID' User ID's home directory
cp -r ~jester/jokes ~ // coppy with "-r" directory to your home directory

man ls // displays the manual pages describing the "ls" command.
     "man -k" searches the NAME section of all manual pages to find what you are looking for. 

finger Greg // displays information about the system user

find //find files
    find ~ -name "poem*"

cat jabber wocky // "concatenate" two files, 
    cat jabber // many people use "cat", rather than "more", to display the contents of a file.

> >> // To send the output from a command such as "cat" to a file, you can use either '>'(overwrite) or '>>'(add to the end).
    cat jabber wocky > poem 

lpr // send to printer, "line printer"
lpq // display print queue
lprm // remove from print queue,  "line printer remove".
     lpr -P hp14 thoughts // send your file to a printer called "hp14" rather than the default one
     lpq -P hp14 //status of all print jobs in the "hp14" queue
     lprm -P hp14 148

df // how much free space left on disk, "disk free"
    df ~
    df .

ps aux // get a detailed list of all processes

| // "pipes" data from one command to another, sends the output of a command as the input to another command.
     cat joke-1 joke-2 | lpr -P zephyr // The output of "cat joke-1 joke-2" is sent directly to the printer

grep //  use "grep" to find patterns in data. 
    grep gold metals //find every occurrence of the word "gold" in file "metals"
    grep rabbit joke*
    cat joke-1 joke-2 | grep rabbit //  list only those lines containing the word rabbit in Jester's joke files
    ps aux | grep rogue

kill PID // kill process,  PID is the ID of the process you want to kill.
kill -9 PID // kill immediately

curl, tcpdump and tshark // These help in monitoring HTTP traffic.


diff file1 file2 // show difference between 2 files
diff -u file1 file2 // clmpares two files, lune by line
diff -r

patch file_new < file.diff //apply changes
patch -p1

diff -u file1 file2 > file.diff
patch < file.diff