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The basics
It's always difficult for new linux users to find the basic commands, without having all the hundreds of useless options in the syntax.
I try here to summarize the basic and most usefull commands with examples (don't you always look for examples?).
Don't hesitate to leave a comment for any other commands suggestions!
Manage folders and files
cd - Change Directory
move to the specified directory
example :
cd /var/logs
ls - List the content of the current directory
example :
ls
Just type ls to have a list.
Usefull options
- Display the details of the files, like date and rights : ls -l
- Display the hidden files : ls -a
Note you can always combine two options like that :
ls -al
mv - MoVe a file or rename it
move a file to another place, OR rename a file. This command will rename a file if both arguments are not path
example
mv myFile.js myNewFile.js
The file called myFile.js will be renamed to myNewFiles.js
If now you specify a path for one of the argument, mv will try to move the file.
example :
mv myFile.js myFolder/myFile.js
Note you don't have to re-type the name of your file, you could write:
mv myFile.js myFolder/
mkdir - Make a Directory
create a directory in the current folder.
example :
mkdir myNewDir
rm - ReMove a file or a directory
Removes a single file. You cannot remove a folder with rm, unless you use the option -r (Recursive) : warning, all the files contained by the folder will be removed!
examples :
rm myFile.js
rm -r myFolder/
Usefull options
- Remove a directory with all its content : rm -r (Recursive)
- Remove a directory containing read-only files : rm -rf (Recursive and Force removing)
Note that to remove a file beginningwith '-', you cannot escape the name (like "\-myFile.js"), you must write something like:
rm ./-myFile.js
cp - CoPy a file or a folder
Copy a file. To copy an entire folder, use the -r option (Recursive)
examples :
cp myFile.js myFile_copied.js
cp -r myFolder/ myFolder_copied/
Useful options
- Copy an entire folder : cp -r (recursive)
du - Disk Usage
Returns the size in kilobytes of the files or folders given in argument.
examples:
du myFile.html
du -h -s *
Useful options:
- Human-readable size: du -h
- Returns size for each folder, and not for each files recursively : du -s
About Searching
Searching for files or text on Linux is very powerfull. Using regular expressions is a considerable advantage.
grep - search text in the given file
grep looks for a given text in all the given file. You can use here the star * to look into all the files of the folder. You can also search in all the subfolders by using the -r (Recursive) option.
example :
grep "I look for you" myTextFile.txt
grep "I look for you" *
grep -r "I look for you" myFolder/
grep -r "I look for you" *
The last example will search in every file of the current folder, and in the subfolders as well.
Note that grep doesn't search in file names! (grep -r "myFile.js" won't return you the path to this file!)
Useful options
- Recursive search in all subfolders : grep -r note you can also often use the equivalent rgrep
- Invert the command, look for lines which does not contain the given string : grep -v
Combining some commands
Using the pipe (|)
Use the pipe operator to build a "super" command! I explain : imagine you want to search a previous command you typed some time ago, a cp for example. The command history will display a list of the last typed command. How can you now get this list, and then search your command in it ? Here comes the pipe operator into play: you would write history | grep "cp" See the trick?
The result of the first command history is given to the second command grep : grep will search in the list returned by history.
Now you can build some super commands, like :
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