Update to a useful bash function

Previously… Useful bash functions

This new version is a tad more efficient since there are no more echo and pipes involved on the processing. Just one eval and one awk script.

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unique_path() {

  eval $(awk -v VAR="${1}" 'BEGIN {                 \

    if((N=split(ENVIRON[VAR],vals,":"))<2) exit(0); \

    sep = out="" ; i=split(out,seen);               \

    do { if(!(vals[++i] in seen)) { seen[vals[i]];  \

           gsub("["]","\\"",vals[i]);             \

           out=sprintf("%s%s%s",out,sep,vals[i]);   \

           sep=":";                                 \

    } } while (i<N);                                \

    printf "%s="%s"; export %s;\n",VAR,out,VAR;   \

  }' /dev/null)

}

Similarly, these also had remove unnecessary uses of sub-shell echo…

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safe_prepend_path() {

  VAR=$1 ; shift ; eval VAL=\$${VAR}

  for i_;do [ -d "$i_" ] && VAL=$i_${VAL:+":$VAL"} ;done

  eval export ${VAR}=${VAL}

}



safe_append_path() {

  VAR=$1 ; shift ; eval VAL=\$${VAR}

  for i_;do [ -d "$i_" ] && VAL=${VAL:+"$VAL:"}$i_ ;done

  eval export ${VAR}=${VAL}

}