parallelで何かする

parallel_ssh.sh

#!/bin/bash

SSH_CONFIG_PATH="${HOME}/.ssh/config"

is_ssh_config_exist() {
    if [[ -f "$SSH_CONFIG_PATH" ]]; then
        return 0
    else
        return 1
    fi
}

is_parallel_installed() {
    if [[ -x "$(which parallel)" ]]; then
        return 0
    else
        return 1
    fi
}

echo_err() {
    echo "ERROR: $1" >&2
}

create_host_name_file() {
    local tmp_file_path=$(mktemp "/tmp/${0##*/}.XXXXXX") || { echo_err "Can't create tmp file"; exit 1; }
    cat "$SSH_CONFIG_PATH" | sed 's/^ \+//g' | grep -vE '(^$|^#|\*)' | grep 'Host ' | cut -d' ' -f2 > "$tmp_file_path"

    echo "$tmp_file_path"
}

_parallel() {
    parallel -u ssh {} 'ip addr show' :::: "$1"
}

rm_tmp_file_on_exit() {
    if [[ -f "$tmp_file_path" ]]; then
        rm "$tmp_file_path"
    fi
}

trap rm_tmp_file_on_exit EXIT

is_ssh_config_exist
if [[ "$?" -ne 0 ]]; then
    echo_err "$SSH_CONFIG_PATH does not exist"
fi

is_parallel_installed
if [[ "$?" -ne 0 ]]; then
    echo_err "$parallel not found"
fi

tmp_file_path=$(create_host_name_file)

_parallel "$tmp_file_path"