Linux

Shell commands & scripting

• editor di testo: nano, vi
• comandi principali: ps, ls, top, ecc.
• bash e scripting: $(command), ${var}, $?[rv], $$[pid], $#[pc], $1[p1], ..., $9[p9]
• variabili semplici
  • COUNTER=20; let COUNTER+=1; let COUNTER-=1;
  • COUNTER="ciao"; ...
• selezione:

  • if true; then
    sleep 1
    echo thinking
    else
    ...
    fi

  • il comando test

  • case $1 in
    0) ;;
    1) ;;
    *) ;;
    esac

• ripetizione:

  • while true; do
    sleep 1
    echo thinking
    done

  • until false; do
    sleep 1
    echo thinking
    done

  • for i in {1..5}; do
    sleep 1
    echo thinking
    done

• array
  • declare -a arrayNAME
  • arrayNAME=(one two three)
  • echo ${arrayNAME[*]}
  • arrayNAME[3]=four
  • echo ${arrayNAME[*]}
  • unset arrayNAME[1]
  • echo ${arrayNAME[*]}
  • unset arrayNAME
  • echo ${arrayNAME[*]}
• array associativi
  • declare -A arrayNAME
  • arrayNAME=( [foo]=bar [baz]=quux [corge]=grault )
  • arrayNAME["hello"]="world"
  • echo ${!arrayNAME[@]}

  • for key in ${!arrayNAME[@]}
    do
    # echo $key ${arrayNAME["$key"]}
    printf '%-*s %*s\n' 80 $key 10 ${arrayNAME["$key"]}
    done

• redirezione e piping, here documents
• comandi di elaborazione: head, tail, grep, cut, sort, ecc.