janmatyoo / my-coding-cheatsheet

Contains all the helpful cheatsheet from various technologies!

My Coding Cheatsheet

Contains all the helpful cheatsheet from various technologies!

Python

Virtual Environment

• python3 -m venv <venv> Create new virtual environment
• source <venv>/bin/activate Activate in Mac
• <venv>\Scripts\activate.bat Activate in Windows
• deactivate Deactivate virtual environment

Shell

File Manipulation

• cp <source-path>/<filename.filetype> <target-path>/<filename.filetype> copies a file from one place to another
• cp <filename.filetype> <filename.filetype> can create a new copy of a file in the same location with a different filename or different file type
• man cp Displays the manual file for the cp command. When viewing a manual file, type q to quit and return to the command line.
• mv blah.txt /home/user/newdir/ Moves the file called blah.txt to the directory /home/user/newdir/
• mv blah.txt blahblah.txt Renames the file blah.txt to blahblah.txt.
• chmod 755 file.php Changes the permissions on file.php to 755 (rwxr-xr-x).
• chown website:website file.php Changes the file.php so that it is owned by the user and group called website.
• rm -f oldindex.php Deletes the file called oldindex.php.
• rm -rf olddirectory/ Deletes the directory/folder called olddirectory.
• cat index.php Displays the entire contents of the file index.php.

Directory

• pwd Displays your location in the directory tree (path)
• cd ~ Changes to your user’s home directory
• cd – Returns you to the previous directory you were working in
• cd .. Moves you one directory up/back in the directory structure
• ls Display directories
• ls -l Display directory contents in a “long list” format.
• ls -lah Display all files, including hidden, with a human-readable file size.

Others

• grep [e-mail] /var/log/exim_mainlog Searches the file exim_mainlog for all instances of the e-mail address [e-mail].
• wget http://domain.com/file.tar.gz Pulls the file ‘file.tar.gz’ from the domain ‘domain.com’
• tail -n 50 /var/log/exim_mainlog Displays the last 50 lines of the file exim_mainlog.
• tail -f /var/log/exim_mainlog Persistently watches the file exim_mainlog as the server makes changes to it (real-time).
• w Displays a list of users who are logged in to the system through a remote shell or local terminal, what they are doing, and other relevant information.
• sudo lsof -i :5955 Find out the process ID (PID) which is occupying the port number (e.g., 5955) you would like to free
• kill PID Kill the process which is currently using the port using its PID