bash.md

Bash programming

Redirect Output

To redirecto the output to a file, and show the output on terminal as well:

command | tee [-a] stdout.log

The following command works always, even if the command is redirecting stdout:

command > >(tee stdout.log) 2> >(tee stderr.log >&2)

Switch case

To define a switch-case:

case $var in
*) # all
    do_stuff1
;;
something)
    do_stuff2
;;
esac 

Arrays

To initialize an array:

declare -a array
array=( one two three )

The number of elements:

num_of_elements=${#array[*]}

for (( i = 0 ; i < num_of_elements; i++ )); do
    echo ${array[i]}
done

Buffers

To read a buffer continuously:

while IFS= read -r line
do
    ...
done </dev/ttyS0