So, I decided to streamline my shell config the other day. The very first I did, was to write an awk replacement in perl. Sounds a little senceless, but sometimes I need some more power inside an awk command and sometimes I just want to save typing. This is how it looks like, when used:

# awk version:
ps | grep sleep | grep -v grep | awk '{print $1}' | xargs kill
# pwk version:
ps | grep sleep | grep -v grep | pwk 1 | xargs kill

This is the simple variant, which just saves typing, pretty handy. The other variant is more perlish and at first looks like the original awk syntax. Hover, you can add almost any kind of perl code to it:

ps | pwk 'if($5 =~ /^python$/) { $t=`fetch -o - "http://$8/"`; if($t =~ /<title>(.+?)<\/title/) { print "$8: $1"} }'

Here's the shell function, just put it into your .bashrc:

pwk () {
    if test -z "$*"; then
        echo "Perl awk. Usage:"
        echo "Perlish: pawk [-F/regex/] [-Mmodule] <perl code>"
        echo " Simple: pawk <1,2,n | 1..n>"
        echo "Perlish helpers:"
        echo "  p() - print field[s], eg: p(\$1,\$4,\$7)"
        echo "  d() - dump variables, without param, dump all"
        echo "  e() - exec code on all fields, eg: e('s/foo/bar/')" 
        echo
        echo "Default loaded modules: Data::Dumper, IO::All"
        echo "Enable \$PWKDEBUG for debugging"
        echo "Simple mode has no helpers or anything else"
    else
        # determin pwk mode
        if echo "$*" | egrep '^[0-9,\.]*$' > /dev/null 2>&1; then
            # simple mode
            code=`echo "$*" | perl -pe 's/([0-9]+?)/\$x=\$1-1;\$x/ge'`      
            perl -lane "print join(' ', @F[$code]);"
        else
            # perl mode
            # prepare some handy subs
            uselib="use lib qw(.);"
            subprint="sub p{print \"@_\";};"
            subsed='sub e{$r=shift; foreach (@F) { eval $r; }};'
            subdump='sub d {$x=shift||{_=>$_,S=>\@F}; print Dumper($x);};'
            begin=";  BEGIN { $uselib $stdsplit $subprint $subdump $subsed}; "
        # extract the code and eventual perl parameters, if any
        code=""
        args=""
        last=""
        for arg in "$@"; do
            args="$args $last"
            last="$arg"
        done
        code=$last
        
        # fix perl -F /reg/ bug, complains about file /reg/ not found,
        # so remove the space after -F
        args=`echo "$args" | sed -e 's/-F /-F/' -e 's/-M /-M/'`
        
        # convert $1..n to $F[0..n]
        code=`echo "$code" | perl -pe 's/\\\$([0-9]+?)/\$x=\$1-1;"\\\$F[\$x]"/ge'`
        
        # rumble
        defaultmodules="-MData::Dumper"
        if perl -MIO::All -e0 &gt; /dev/null 2&gt;&amp;1; then
            defaultmodules="$defaultmodules -MIO::All"
        fi
        
        if test -n "$PWKDEBUG"; then
            set -x
        fi
        perl $defaultmodules $args -lane "$code$begin"
        if test -n "$PWKDEBUG"; then
            set +x
        fi
    fi
fi

}

Another new shell function is extr, which unpacks any kind of archive. In contrast to its sisters out there (there are a couple of generic unpack shell funcs to be found on the net), it takes much more care about what it does. Error checking, you know. And it looks inside the archive to check if it extracts into its own directory, which is not always the case and very annoying. In such instances it generates a directoryname from the archivename and extracts it to there. Usage is simple: extr archivefile. Here's the function:

extr () {
    act() {
        echo "$@"
        "$@"
    }
    n2dir() {
        tarball="$1"
        suffix="$2"
        dir=`echo "$tarball" | perl -pne "s/.$suffix//i"`
        dir=`basename "$dir"`
        echo "$dir"
    }
    tarball="$1"
    if test -n "$tarball"; then
        if test -e "$tarball"; then
            if echo "$tarball" | grep -Ei '(.tar|.jar|.tgz|.tar.gz|.tar.Z|.tar.bz2|tbz)$' > /dev/null 2>&1; then
                # tarball
                if echo "$tarball" | grep -E '.(tar|jar)$' > /dev/null 2>&1; then
                    # plain old tarball
                    extr=""
                elif echo "$tarball" | grep -E '(bz2|tbz)$' > /dev/null 2>&1; then
                    extr="j"
                elif echo "$tarball" | grep -E 'Z$' > /dev/null 2>&1; then
                    extr="Z"
                else
                    extr="z"
                fi
            if ! tar ${extr}tf "$tarball" | cut -d/ -f1 | sort -u | wc -l
                | egrep ' 1$' > /dev/null 2>&1; then
                # does not extract into own directory
                dir=`n2dir "$tarball" "(tar.gz|tgz|tar.bz2|tbz|tar|jar|tar.z)"`
                mkdir -p $dir
                extr="-C $dir -${extr}"
            fi
            act tar ${extr}vxf $tarball
        elif echo $tarball | grep -Ei '.zip$' > /dev/null 2>&1; then
            # zip file
            if unzip -l "$tarball" | grep [0-9] | awk '{print $4}' | cut -d/ -f1 | sort -u \
                | wc -l | egrep ' 1$' /dev/null 2>&1; then
                # does not extract into own directory
                dir=`n2dir "$tarball" zip`
                act mkdir -p $dir
                opt="-d $dir"
            fi
            act unzip ${opt} $tarball
        elif echo "$tarball" | grep -Ei '.rar$' > /dev/null 2>&1; then
            if ! unrar vt "$tarball" | tail -5 | grep '.D...' > /dev/null 2>&1; then
                # does not extract into own directory
                dir=`n2dir "$tarball" rar`
                act mkdir -p "$dir"
                (cd "$dir"; act unrar x -e $tarball)
            else
                act unrar x $tarball
            fi
        elif echo "$tarball" | grep -Ei '.gz$' > /dev/null 2>&1; then
            # pure gzip file
            act gunzip "$tarball"
        else
            :
        fi
    else
        echo "$tarball does not exist!"
    fi
else
    echo "Usage: untar <tarball>"
fi

}

And finally an updated version of my h function, which can be used for dns resolving. Usage is pretty simple:

% h theoatmeal.com
; dig +nocmd +noall +answer theoatmeal.com
theoatmeal.com.         346     IN      A       208.70.160.53
% h 208.70.160.53
; dig -x 208.70.160.53 +short
oatvip.gpdatacenter.com.
% h theoatmeal.com mx
; dig +nocmd +noall +answer theoatmeal.com mx
theoatmeal.com.         1800    IN      MX      5 eforwardct2.name-services.com.
theoatmeal.com.         1800    IN      MX      5 eforwardct3.name-services.com.
theoatmeal.com.         1800    IN      MX      5 eforwardct.name-services.com.

It uses dig to do the work, or host if dig cannot be found. The source:

h () {
    if type dig > /dev/null 2>&1; then
        args="$*"
        opt="+nocmd +noall +answer"
        rev=""
        if echo "$args" | egrep '^[0-9\.:]*$' > /dev/null 2>&1; then
            # ip address
            cmd="dig -x $* +short"
        else
            # hostname
            cmd="dig +nocmd +noall +answer $*"
        fi
        echo "; $cmd"
        $cmd
    else
        # no dig installed, use host instead
        host="$1"
        type="a"
        debug=""
        cmd="host $debug"
        if test -z "$host"; then
            echo "Usage: h <host> [<querytype>]"
            return
        else
            if test -n "$2"; then
                type=$2
            fi
            if test -n "$debug"; then
                set -x
            fi
            case $type in
                ls)
                    $cmd -l $host
                    ;;
                any)
                    cmd=`echo $cmd | sed 's/\-d//'`
                    $cmd -d -t any $host | grep -v ^\; | grep -v "^rcode ="
                    ;;
                mx|a|ns|soa|cname|ptr)
                    $cmd -t $type $host
                    ;;
                *)
                    echo "*** unsupported query type: $type!"
                    echo "*** allowed: mx, a, ns, any, *, soa, cname, ptr"
                    continue
                    ;;
            esac
            if test -n "$debug"; then
                set +x
            fi
        fi
    fi
}

So, after a couple of idle years I made an update to my subst script. Although I use it everyday there were still some glitches here and there. For one, I just could not rename files with spaces in them. Very annoying. Also it was unflexible in that I could not use additional perlmodules when using /e. STDIN was not supported among other minor stuff.

So, the new version fixes all this, see the link above. Download, rename it (remove the .txt extension) and put it into your bin directory. Usage:

Usage: subst  [-M <perl module>] [-t] -r 's/old/new/<flags>' [ -r '...', ...] [<file> ...     | /regex/]
       subst  [-M <perl module>] [-t] -m 's/old/new/<flags>' [ -m '...', ...] [<file|dir> ... | /regex/]
Options:
-r        replace contents of file(s)
-m        rename file(s)
-M        load additional perl module to enhance /e functionality.
-t        test mode, do not overwrite file(s)
Samples:


replace “tom” with “mac” in all *.txt files:
subst -r ’s/tom/mac/g’ *.txt


rename all jpg files containing whitespaces:
subst -m ’s/ /_/g’ ‘/.jpg/’


decode base64 encoded contents
subst -M MIME::Base64 -r ’s/([a-zA-Z0-9]*)$/decode_base64($1)/gem’ somefile


turn every uri into a link
subst -M “Regexp::Common qw /URI/” -r ’s#($RE{URI}{HTTP})#<a href="$a">link</a>#g’ somefile


If <file> is -, STDIN will be used as input file, results will be printed
to STDOUT. -t does not apply for STDIN input.
Substitution regex must be perlish. See ‘perldoc perlre’ for details.
Version: 1.1.3. Copyright (c) 2002-2014 - T.v.Dein <tom AT linden DOT at>

So, in order to remove spaces of filenames, I can now just issue:

subst -m 's/ /_/g' '/\.mp3$/'

As you can see, instead of giving a shell wildcard as last argument, I provide a regex, which will be resolved by the script itself from the current directory. Bam!

Ohne Worte:

host -t aaaa ipv4.l.google.com
ipv4.l.google.com has IPv6 address 2a00:1450:4019:800::1003

Frauchen baut ja jedes Jahr massenweise Grünzeug als Futtermittel an. Dieses Jahr ist das hier die erste Blüte ihrer Aussaat:

2014-05-18 - Blüten wilder Stiefmütterchen:

Man beachte diese beiden Heisemeldungen:

1. 05.05.2014 20:47: Springer: Google, Facebook & Co. "wollen uns Verlage vernichten"

2. 06.05.2014 08:23: Axel Springer erwirtschaftet erstmals mehr als die Hälfte seines Umsatzes digital

Offensichtlich setzen die zu viele unbezahlte Praktikanten in ihrer PR-Abteilung ein. Demagogengesindel.