user/check_order.sh

   1 #!/bin/bash
   2 # Desc: Checks stdin for lines out of order.
   3 # Input: stdin
   4 # Output: stdout
   5 # Version: 0.0.1
   6
   7 yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
   8 die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
   9 must() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
  10 read_stdin() {
  11     # Desc: Consumes stdin; outputs as stdout lines
  12     # Input: stdin (consumes)
  13     # Output: stdout  (newline delimited)
  14     #         return  0  stdin read
  15     #         return  1  stdin not present
  16     # Example: printf "foo\nbar\n" | read_stdin
  17     # Depends: GNU bash (version 5.1.16), GNU Coreutils 8.32 (cat)
  18     # Version: 0.1.1
  19     # Attrib: Steven Baltakatei Sandoval (2024-01-29). reboil.com
  20     local input_stdin output;
  21
  22     # Store stdin
  23     if [[ -p /dev/stdin ]]; then
  24         input_stdin="$(cat -)" || {
  25             echo "FATAL:Error reading stdin." 1>&2; return 1; };
  26     else
  27         return 1;
  28     fi;
  29
  30     # Store as output array elements
  31     ## Read in stdin
  32     if [[ -n $input_stdin ]]; then
  33         while read -r line; do
  34             output+=("$line");
  35         done < <(printf "%s\n" "$input_stdin") || {
  36             echo "FATAL:Error parsing stdin."; return 1; };
  37     fi;
  38
  39     # Print to stdout
  40     printf "%s\n" "${output[@]}";
  41
  42     return 0;
  43 }; # read stdin to stdout lines
  44 main() {
  45     previous="";
  46     n=1;
  47     while IFS= read -r line; do
  48         current="$line";
  49         if [[ -n "$previous" ]] && [[ "$previous" > "$current" ]]; then
  50             yell "STATUS:Line $n is out of order: $line";
  51         fi;
  52         previous="$current";
  53         ((n++));
  54     done < <(read_stdin || die "FATAL:No stdin.");
  55 }; # main program
  56 export -f read_stdin;
  57
  58 main "$@";
  59
  60 # Author: Steven Baltakatei Sandoval
  61 # License: GPLv3+