Bits of handy code

Bits of handy code

Some handy code which is useful when its really needed.

1. pretify json via commandline
   cat myfile.json | python -m json.tool
2. Start Unetbootin in debian. change sudo to su accordingly.
   sudo export QTX11NO_MITSHM=1 unetbootin
   archlinux forum
3. Reset git HEAD
   git reset HEAD~1
4. Include full path in the output of find command for current directory
   find -name "filename" -exec readlink -f {} \;
5. Execute a command on the files found with find command.
   find -iname "*.pdf" -exec cp "{}" /destination/directory \;
6. Check progress of dd command while writing to a drive. Very useful while creating bootable pen drives Create bootable drive
   dd if=[iso path] of=[device] bs=4 While the above command is running open another terminal and give this command and check output in previous terminal
   watch -n5 'sudo kill -USR1 $(pgrep ^dd)'
7. To encrypt file or folder from cli. make sure you have gpg and tar
   tar zcvf - [file1|folder1] [file2|folder2] | gpg -c > myfiles-backup.tar.gz.gpg
   this will ask for passphrase
   and to decrypt
   gpg myfiles-backup.tar.gz.gpg
   For more details
8. How to come out of ssh connections that got closed or froze.
   Enter, ~, . type these on the terminal whose connection is lost
9. Play music from a folder and sub folders
   mplayer -playlist <(find "$PWD" -name "*.mp3" -type f)
10. One command to backup whole system
    rsync -aAXv --exclude={"/dev/","/proc/","/sys/","/tmp/","/run/","/mnt/","/media/*","/lost+found"} / /path/to/backup/folder
    for more details check this link
    Arch Linux Page
11. Running x11 applications in wayland especially chromium
    GDK_BACKEND=x11 chromium
12. Get ip address from /proc without the use of any net command.
    cat /proc/net/fib_trie | grep "|--" | egrep -v "0.0.0.0"| 127."

Postgresql Quick commands to create Database, Users and other tasks

Create User

CREATE USER <username> WITH PASSWORD '<password>';

Create a Database

CREATE DATABASE <database name>;

Grant Privileges to user on the Database

GRANT ALL PRIVILEGES ON DATABASE <database name> TO <user>;

Change ownership of the Database

ALTER DATABASE <db name> OWNER TO <user>;

Update user password

ALTER USER <user> WITH PASSWORD '<new password>';

Drop Database or user or table

DROP DATABASE <db name>;
DROP USER <user>;
DROP TABLE <table>;

Clear records and keep the structure of the table

TRUNCATE <table>;

Grant privileges to a table for a user

GRANT ALL PRIVILEGES ON TABLE <table> TO <user>;

Grant privileges to user for importing files (improt csv to Database)

GRANT pg_read_server_files TO <user>;