convert-logs-dateext

#!/bin/bash
# Rename log files of the form BASE.[NUMBER].gz to BASE-[DATE].gz
set -eu

declare -a default_exts=('' 'gz')
syslogs="syslog mail.info mail.warn mail.err mail.log daemon.log kern.log auth.log user.log local1.log lpr.log cron.log debug messages"

exts_string=
for e in "${default_exts[@]}"; do
    exts_string="$exts_string '$e'"
done

usage() {
    cat >&2 <<EOM
usage: $(basename "$0") [OPTIONS] [LOGS...]

Rename log files of the form BASE.[NUMBER][.EXT] to BASE-[DATE][.EXT]

Options:
    -h          Display this help.
    -e EXT      Add EXT as a valid file extension. Default$exts_string.
    -y          Automatically concatenate files for the same date.
    -s          Use a default set of syslog files:

$(echo "$syslogs" | fold -sw 60 | sed -e 's/^/                    /')

EOM
}

declare -a exts=()
auto_append=
logs=

while getopts he:ys OPT; do
    case $OPT in
        h)
            usage
            exit 0
            ;;
        e)
            if [ "${#exts[@]}" -eq 0 ]; then
                exts=("$OPTARG")
            else
                exts=("${exts[@]}" "$OPTARG")
            fi
            ;;
        y)
            auto_append=1
            ;;
        s)
            logs="$syslogs"
            ;;
    esac
done

shift $((OPTIND-1))

# set exts to defaults if -e not given
if [ "${#exts[@]}" -eq 0 ]; then
    exts=("${default_exts[@]}")
fi

# must specify args if -s was not given
if [ -z "$logs" ]; then
    if [ $# -lt 1 ]; then
        usage
        exit 1
    fi
fi

# add args to logs
logs="$logs $*"

shopt -s nullglob

echo -n "extensions: "
for ext in "${exts[@]}"; do
    echo -n "'$ext' "
done
echo ''
echo "logs: $logs"

run() {
    echo >&2 "+ $*"
    "$@"
}

# atomic_append FIRST SECOND TARGET
# Concatenate FIRST and SECOND, then atomically replace TARGET with the result.
# Take file permissions and mtime from SECOND.
atomic_append() {
    first="$1"
    second="$2"
    target="$3"

    tmpf="$(mktemp)"
    trap "rm -fv '$tmpf'" EXIT

    echo "+ cat $first $second > $tmpf"
    cat "$first" "$second" > "$tmpf"

    if [ "$(id -u)" = "0" ]; then
        run chown --reference "$second" "$tmpf"
    fi
    run chmod --reference "$second" "$tmpf"
    run touch --reference "$second" "$tmpf"

    run mv -v "$tmpf" "$target"

    trap - EXIT
}

for name in $logs; do
    for ext in "${exts[@]}"; do
        if [ -n "$ext" ]; then
            ext=".$ext"
        fi
        echo "looking for $name.\d{1,3}$ext"
        for file in $name.{[0-9],[0-9][0-9],[0-9][0-9][0-9]}$ext; do
            if [ -n "$ext" ]; then
                number=$(echo "$file" | awk -F . '{ print $(NF-1) }')
            else
                number=$(echo "$file" | awk -F . '{ print $NF }')
            fi
            orig="$name.$number$ext"
            rdate=$(stat -c "%y" "$orig" | cut -f 1 -d' ' | tr -d -)
            dateext="$name-$rdate$ext"
            echo "* $orig"

            if [ -e "$dateext" ]; then
                echo "$dateext already exists."
                if [ "$orig" -nt "$dateext" ]; then
                    echo "$orig is newer than $dateext, will append"
                    append=1
                else
                    echo "$orig is older than $dateext, will prepend"
                    append=
                fi

                if [ -n "$auto_append" ]; then
                    ans=y
                else
                    ans=
                    read -p "Combine them into one file? [Y/n] " ans
                fi

                if [ "$ans" = "y" -o "$ans" = "Y" ]; then
                    if [ -n "$append" ]; then
                        # append
                        atomic_append "$dateext" "$orig" "$dateext"
                        rm -fv "$orig"
                    else
                        # prepend
                        atomic_append "$orig" "$dateext" "$dateext"
                        rm -fv "$orig"
                    fi
                else
                    echo "Taking no action."
                fi
            else
                mv -iv "$orig" "$dateext"
            fi
        done
    done
done

echo 'done!'