I personally prefer terminal instead of GUI to do simple and complex job. The first time I learned how to use Ubuntu, I also learned how to use the bash terminal. I found the following bash commands saved me to do various simple job.
ls
ls stands for list and is used to display the list of folders and files in the current working directory. There are two flags we are going to use regularly: -a (to list all files including hidden files) and -l (to use long format display).
The following command will display all folder and files in current working directory:
ls -al
If we want to display other directory instead of current working directory, we can specify the path in the ls command.
The following will display all folders and files in $HOME directory:
ls -al ~
If we only need to display a spesific file, here’s command that we can use to display only files with html extension:
ls -al ~ *.html
cd
cd stands for change directory. Suppose we don’t know the folder structure, we can list all folders by using ls command. The following command will move us to /usr/bin:
cd /usr/bin
There are two arguments that contains only dot, they are:
.refers to current directory..is used to move up one folder
Suppose we are now in $ROOT folder and need to move to /usr/bin folder. We can run the following command to achive the need:
cd ./usr/bin
Now, we are in /bin/usr folder. To move up to /bin folder, we can simply run the following command:
cd ..
The .. can be used to as many as we need it. If we are in /bin/usr folder and want to move to / folder, just run the following command:
cd ../..
If we are in /bin/usr folder and want to move to /etc/apt folder, the following command can be run to achieve the need:
cd ../../etc/apt
mkdir
mkdir stands for make directory. A useful flag that can be used is p to ensure it creates parents folders as well if they don’t exist already. The following command will create page1 folder and will also create docs folder if it doesn’t exist as page1 folder’s parents:
mkdir -p $HOME/docs/page1
touch
We have successfully create a new directory using mkdir command. To create an empty file, we can use touch command. Run the following command to create an empty file named go.sh in current working directory:
touch go.sh
The touch command is actually used to update the access and or modification date of a file or directory without opening, saving or closing the file.
cat
cat is a command to concatenate and display files’ content to stdout. To add a bunch of line of text at the end of file, run the following command:
cat >> filename
After run the preceding command, we can write the text line to the console. Press Ctrl+D to insert inputed text in the end of filename file.
To create a new file instead of inserting text, we can run the following command to create a new file named filename:
cat > filename
mv
mv stands for moveand is used to move files or folders. It need at least two arguments: SOURCE and DESTINATION. For instance, the following is command to move $HOME/app to /usr/bin:
mv ~/app /usr/bin
After successfully running the preceding command, we will have /usr/bin/app folder.
cp
cp stands for copy and is used to copy selected files or folders to another folder. Similar to mv command, it needs SOURCE and DESTINATION arguments too. The difference with mv command is SOURCE in cp command will still be there. The following command will copy file named file.sh in $HOME to $HOME/doc2 folder:
cp ~/file1.sh ~/doc2
To copy a folder, we need to add -r flag which means recursively. The following command will copy doc2 folder and all its content in $HOME directory to $HOME/doc folder:
cp -r ~/doc2 ~/doc
rm
rm stands for remove and is used to delete files or folders. The following command will delete file.sh in current active directory:
rm file1.sh
To delete a directory, similar to cp command, we have to specify -r flags as well. The following will delete doc1 folder in $HOME directory:
rm -r ~/doc1
NOTE: rm -r / will remove all folders and file inside / folder which means it will delete all contents in our computer.
chmod
chmod stands for change mode and is used to set file or folder permission for read, write, and execute for the user, members of current group and others. It denote by three octal digit representing binary value.
man
man stands for manuals and is used to print out the instruction of specified command.
Source links:
Top 10 Bash file system commands you can’t live without
Bash scripting cheatsheet
13 Basic Cat Command Examples in Linux
Linux chmod command