69 lines
1.2 KiB
Bash
69 lines
1.2 KiB
Bash
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#!/usr/bin/env bash
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set -eEou pipefail
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die() {
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printf "%s\n" "${*}"
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exit 1
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}
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usage() {
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local script
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script="$(basename "${0}")"
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cat <<-__EOS__
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==== USAGE ====
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Provide a file:
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${script} ./some/path/to/a/file
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Pipe from stdin:
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echo "hello\nworld!" | ${script}
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Redirect from stdin:
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${script} < ./some/path/to/a/file
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==== USAGE ====
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__EOS__
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}
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handle_lines() {
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local input="${1}"
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local line_count=0
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while read -r line; do
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# To satisfy the `set -u` incantation at the top, we have to assign the variable instead of
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# a simple ((line_count++))
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line_count=$((line_count + 1))
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if ((line_count % 2 == 0)); then
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printf "%s\n" "$line"
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fi
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done <"$input"
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if ((line_count > 10)); then
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printf "big\n"
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else
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printf "small\n"
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fi
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}
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main() {
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# Check if we should read from stdin or a given file
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if [[ -t 0 ]]; then
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# Input should be a path to a file
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set +u
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if [[ -z "${1}" ]]; then
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usage
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die "No input received!"
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fi
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set -u
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local fpath="${1}"
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if ! [[ -r "$fpath" ]]; then
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die "Unable to read a file at: ${fpath}"
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fi
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handle_lines "$fpath"
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else
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# Read from stdin
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handle_lines "/dev/stdin"
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fi
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}
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main "${@}"
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