#!/usr/bin/env bash
set -euo pipefail

echo {1..10} # => 1 2 3 4 5 6 7 8 9 10
echo {a..z} # => a b c d e f g h i j k l m n o p q r s t u v w x y z
# This will output the range from the start value to the end value.
# Note that you can't use variables here:
from=1
to=10
echo {$from..$to} # => {$from..$to}
echo {{1..3},{7..9}} # =>  1 2 3 7 8 9

for item in a b c; do echo "$item"; done

for item in ./example-dir/example-pattern*; do
  echo "$item"
done

while true; do 
  # example_command_to_execute
  echo "--- sleep 10 ---"
  sleep 10
done

cat file.txt | while read line; do
  echo $line
done

str="/path/to/foo.cpp"
echo "$str"           # /path/to/foo (variable expansion)
echo "${str}"         # /path/to/foo (variable expansion)
echo '$str'           # '$str' (disabled variable expansion)
echo "${str%.cpp}"    # /path/to/foo
echo "${str%.cpp}.o"  # /path/to/foo.o
echo "${str%/*}"      # /path/to

echo "${str##*.}"     # cpp (extension)
echo "${str##*/}"     # foo.cpp (basepath)

echo "${str#*/}"      # path/to/foo.cpp
echo "${str##*/}"     # foo.cpp

echo "${str/foo/bar}" # /path/to/bar.cpp

$1 # first argument passed to a script or function
$# # the number of arguments passed to a script or functio
$* # all the arguments passed to a script or function, treating them as a single string
$@ # all the arguments passed to a script or function, treating them as an array

git commit && git push
git commit || echo "Commit failed"

echo "Current directory: $PWD"

VAR=value  echo $VAR
#VAR=value  command_with_var

current_date=$(date)

cat ~/.bashrc | grep -v '#' | grep -v '^$'

echo "echo 'bash is executed:' \$1" | bash -s 'arg1'

if ping -c 1 google.com; then
  echo "It appears you have a working internet connection"
fi

printf "Hello %s, I'm %s" Sven Olga
#=> "Hello Sven, I'm Olga

printf "1 + 1 = %d" 2
#=> "1 + 1 = 2"

printf "This is how you print a float: %f" 2
#=> "This is how you print a float: 2.000000"

printf '%s\n' '#!/bin/bash' 'echo hello' >file
# format string is applied to each group of arguments
printf '%i+%i=%i\n' 1 2 3  4 5 9

python hello.py > output.txt            # stdout to (file)
python hello.py >> output.txt           # stdout to (file), append
python hello.py 2> error.log            # stderr to (file)
python hello.py 2>&1                    # stderr to stdout
python hello.py 2>/dev/null             # stderr to (null)
python hello.py >output.txt 2>&1        # stdout and stderr to (file), equivalent to &>
python hello.py &>/dev/null             # stdout and stderr to (null)
echo "$0: warning: too many users" >&2  # print diagnostic message to stderr

$((a + 200))      # Add 200 to $a

if [[ -e "file.txt" ]]; then
  echo "file exists"
fi

myfunc() {
    echo "hello $1"
}
## call in an expansion
echo "result: $(myfunc foo)"
## call as a command
myfunc bar