====== Programming ======
http://rogerdudler.github.io/git-guide/

===== Bash =====
FIXME

==== root-check ====
<code bash>
if [ $UID -eq 0 ];then echo "root";fi
</code>
==== online-check ====
<code bash>
  ping -c 1 ${HOST} -W 1 >/dev/null
  if [ $? == 0 ];
  then
  
  fi
</code>
==== colors ====
<code bash>
clr_red=$'\e[1;31m'
clr_green=$'\e[1;32m'
clr_yellow=$'\e[1;33m'
clr_blue=$'\e[1;34m'
clr_reset=$'\e[0m'
</code>
<code bash>
 echo ${clr_red}test${clr_reset}
</code>

==== logging ====
log single command (only stderr) and view simultaneously (stdout+stderr)
<code bash>
#via Process Substitution (https://www.gnu.org/software/bash/manual/bash.html#Process-Substitution)
make 2> >( tee "$logfile" ) ; echo $?
</code>
log multiple lines/commands:
<code bash>
exec 3> >(tee logfile)

make alpha 2>&3 &&
make bravo 2>&3 &&
make charlie 2>&3 && success=1

exec 3>&-
</code>

==== Case ====

  case "$string" in 
    *foo*)
      #anything
    ;;
    [1-6]*)
      #number-ranges
    ;;
    *)
      #all other
    ;;
  esac
==== stringmanipulation ====
In Bash 4:
all lowercase

  $ echo "${string,,}"

all uppercase:

  $ echo "${string^^}"

[[https://stackoverflow.com/questions/2264428/converting-string-to-lower-case-in-bash|Quelle]]

=== path / filename ===

<code bash>
  $ VAR=/home/me/mydir/file.c
  $ DIR=$(dirname "${VAR}")
  $ echo "${DIR}"
  /home/me/mydir
  $ basename "${VAR}"
  file.c
</code>

=== substrings ===

  a=string
  b=${a:p:l}
  #p=Position (0-basiert),l=Länge

=== replace ===

  orig="AxxBCyyyDEFzzLMN"
  mod=${orig//[xyz]/_}

=== Regex-Check ===

<code bash>
string='My string';
  
if [[ $string =~ .*My.* ]]
then
  echo "It's there!"
fi
</code>
==== calculation ====

  GPIO_NO=$((232+25))

==== Number-Ranges ====

  ls IMG_20170923_{17..18}*

==== terminal language ====

temporary change language (e.g. to get errors in english for forums):

  LANG=C
===== Batch =====
===== C/C++ =====
===== CSS =====
===== JavaScript =====
===== HTML =====
===== PHP =====