| 1 | #!/usr/bin/env bash |
| 2 | # Desc: Gets random line from a newline-delimited file |
| 3 | # Usage: get_rand_line [path FILE] |
| 4 | # Version: 0.0.1 |
| 5 | |
| 6 | yell() { echo "$0: $*" >&2; } # print script path and all args to stderr |
| 7 | die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status |
| 8 | must() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails |
| 9 | get_rand_line() { |
| 10 | # Input: arg1 : file path |
| 11 | # stdout: random line from input file |
| 12 | # Usage: get_rand_line [path FILE] |
| 13 | # Depends: GNU Coreutils 8.32 (shuf) |
| 14 | |
| 15 | # Check if file |
| 16 | if [[ ! -f "$1" ]]; then die "FATAL:Not a file:$1"; fi; |
| 17 | if [[ $# -ne 1 ]]; then die "FATAL:Incorrect argument count:$1"; fi; |
| 18 | |
| 19 | # Get line count |
| 20 | lc="$(wc -l "$1" | awk '{print $1}')"; |
| 21 | |
| 22 | # Calc random line number (zero-indexed) |
| 23 | ln="$(shuf -i 0-"$((lc - 1))" -n1)"; |
| 24 | |
| 25 | n=0; |
| 26 | while read -r line; do |
| 27 | # Check if line is target line |
| 28 | if [[ $n -eq $ln ]]; then |
| 29 | printf "%s\n" "$line"; # output |
| 30 | fi; |
| 31 | ((n++)); |
| 32 | done < "$1"; |
| 33 | }; # Returns random line from newline-delimited file |
| 34 | main() { |
| 35 | get_rand_line "$@"; |
| 36 | }; |
| 37 | |
| 38 | main "$@"; |