Bash

Bash is a command line tool and language.

Files

List files

Number of files in a provided directory

```bash ls [myDirectory] | wc -l

### Manipulate Files

Remove directory tree with all its contents
: ```bash
rm -rf [myDirectory]

File Permissions

Show access permissions of file in directory

```bash ls -l [myDirectory]

Change permissions of file
: ```bash
chmod u=rwx,g=rwx,o=rwx [myFile]

Explanation

Control structures

Use commandline arguments

while getopts :c:t flag
do
  case "${flag}" in
      c) 
          config=${OPTARG}
          python3 file_to_be_called.py -c $config
          ;;
      t)
          python3 file_to_be_called.py -t
          ;;
      :) 
          echo "No arguments passed"
          exit 1
          ;;
      ?) 
        echo "Please call the script like this: bash_script.sh [-c config_file]"
        exit 1
        ;;
  esac
done

The : before the flag-character c lets you handle errors yourself (e.g. no arguments passed and wrong arguments passed). The : after the flag-character c indicates that a value is required after the flag.

Processes

List running processes

```bash htop

Commands                                      | 
----------------------------------------------|---
Help                                          | 
Kill process                                  | <kbd>k</kbd>
Order processes by memory consumption         | 
Filter processes by user                      | 
Display files used by the selected process    | 
Display user threads                          | 

:  {tbl-colwidths="[50,50]"}

Kill process
: ```bash
kill -9 [process-PID]

Info on resource usage & processes on NVidia graphic cards

nvidia-smi