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--- en:programming:start [2017/10/21 16:08] – created frank
+++ en:programming:start [2023/06/08 17:06] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== 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 =====