Copy the file to /etc/bash_completion.d or possibly /usr/share/bash-completion/completions or to another place where it is loaded when your Bash shell is started.
The Rails generator script/generate knows pretty well what things it can generate. In fact, it knows much better than I do. So, I think it could really give me some help when I’m typing along on the command line.
If you save the snippet below as /etc/bash_completion.d/generate you can enjoy this help, too.
_generate()
{
local cur
COMPREPLY=()
cur=${COMP_WORDS[COMP_CWORD]}
if [ ! -d "$PWD/script" ]; then
return 0
fi
if [ $COMP_CWORD == 1 ] && [[ "$cur" == -* ]]; then
COMPREPLY=( $( compgen -W '-h -v\\
--help --version'\\
-- $cur ))
return 0
fi
if [ $COMP_CWORD == 2 ] && [[ "$cur" == -* ]]; then
COMPREPLY=( $( compgen -W '-p -f -s -q -t -c\\
--pretend --force --skip --quiet --backtrace --svn'\\
-- $cur ))
return 0
fi
COMPREPLY=( $(script/generate --help | \\
awk -F ': ' '/^ (Plugins|Rubygems|Builtin|User):/ { gsub(/, */, "\n", $2); print $2 }' | \\
command grep "^$cur" \\
))
}
complete -F _generate $default generate
The gem command is the command line user interface to the RubyGems system for managing Ruby packages.
This command has a few sub-commands itself and a long list of options that differ per sub-command. Remembering and typing them can be tedious, but thankfully, if you are using the bash command shell, it can help with this task. It only has to be told how.
I’ve packaged the how in this file. Copy it to /etc/bash_completion.d and hope that your bash installation picks it up the next time you start a shell.
On Debian/Linux system that’s just how it works. If this does not work on your particular version of Linux or Unix, you’ll have to look up how completions are handled on your system.
In order to keep multiple versions of a file, I sometimes add a timestamp to the filename. Doing this by hand is tedious and error-prone, but this chore can be automated by a small shell script.
/usr/local/bin/timestamp
#! /bin/sh
for oldname ; do
ts=`date +'%Y%m%d%H%M' --reference="$oldname"`
newname=`echo $oldname | sed -nre "s/^(\\.?)([^\\.]+)(-[[:digit:]]{12})(\\..*)\$/\\1\\2-$ts\\4/p"`
if [ -z "$newname" ]; then
newname=`echo $oldname | sed -nre "s/^(\\.?)([^\\.]+)(\\..*)\$/\\1\\2-$ts\\3/p"`
fi
if [ -z "$newname" ]; then
newname=`echo $oldname | sed -nre "s/^(\\.?)([^\\.]+)(-[[:digit:]]{12})\$/\\1\\2-$ts/p"`
fi
if [ -z "$newname" ]; then
newname=`echo $oldname | sed -nre "s/^(\\.?)([^\\.]+)\$/\\1\\2-$ts/p"`
fi
if [ -f "$newname" ]; then
if [ "$newname" != "$oldname" ]; then
echo "Can't rename $oldname to $newname: file already exists."
fi
else
echo mv "$oldname" "$newname"
mv "$oldname" "$newname"
fi
done
As I’m using KDE as my desktop, I like to have the timestamping integrated. Fortunately, it’s easy.
~/.kde/share/apps/konqueror/servicemenus
Actions=timestamp ServiceTypes=all/all [Desktop Action timestamp] Exec=/usr/local/bin/timestamp %u Icon=clock Name=Timestamp
See Creating Konqueror Service Menus for a general introduction.
I’ve updated the script to insert the timestamp before all the first extension and to also work with filename starting with a ‘.‘.
I’m using rsnapshot for making regular backups of my Linux box. Neither the computer, nor the external backup disk is running all the time, therefore it would not work to simply have cron run rsnapshot at fixed times.
I want a little more flexibility than that. When the computer is off, there’s no point in making a snapshot. Fine, there’s no work left to handle that case. But in cases where the computer is running, but the backup disk is not, I want it to be recorded that something should have been done–if only the disk had been on. Then, next time the disk is running again, the recorded (queued) tasks are executed in order.
As there are multiple processes involved, for enqueueing tasks and for dequeueing them, and as the later can take some time, there’s a bit of mutual exclusing involved. Luckily, Debian GNU/Linux provides very useful helper programs in the lockfile-progs package.
/usr/local/lib/snapshot/dequeue
#! /bin/sh QUEUEFILE=/var/lib/snapshot/queue LOCKFILE=/var/lib/snapshot/LCK..queue lockfile-create $LOCKFILE if ! test -f $QUEUEFILE || ! grep -Fqs -- "$*" $QUEUEFILE ; then echo $* >> $QUEUEFILE fi lockfile-remove $LOCKFILE
/usr/local/lib/snapshot/dequeue
#! /bin/sh
SNAPDIR=/var/cache/rsnapshot
QUEUEFILE=/var/lib/snapshot/queue
LOCKFILE=/var/lib/snapshot/LCK..queue
PIDFILE=/var/run/snapshot.pid
test -f $PIDFILE && exit 0
test -s $QUEUEFILE || exit 0
echo $$ > $PIDFILE
was_mounted=0
if egrep -qs "\\B$SNAPDIR\\b" /etc/mtab; then
was_mounted=1
mount -o remount,rw $SNAPDIR 2> /dev/null
else
mount -o rw $SNAPDIR 2> /dev/null
fi
if [ $? != 0 ]; then
rm -f $PIDFILE
exit 0
fi
cleanup ()
{
if [ $was_mounted == 1 ]; then
mount -o remount,ro $SNAPDIR
else
umount $SNAPDIR
fi
rm -f $PIDFILE
}
trap "cleanup" EXIT TERM INT
while true; do
lockfile-create $LOCKFILE
if [ -f $QUEUEFILE ] ; then
ARGS=`head -n1 $QUEUEFILE`
sed -i '1d' $QUEUEFILE
fi
lockfile-remove $LOCKFILE
if [ -n "$ARGS" ]; then
nice rsnapshot $ARGS
else
break
fi
done
exit 0
Things are tied together by several cron jobs that define when things should, if possible, happen. Of course, this is highly dependent on the individual rsnapshot configuration.
/etc/cron.d/snapshot
7 12,20 * * * root /usr/local/lib/snapshot/enqueue hourly 11 20 * * * root /usr/local/lib/snapshot/enqueue daily 13 20 * * 1 root /usr/local/lib/snapshot/enqueue weekly 17 20 1 * * root /usr/local/lib/snapshot/enqueue monthly */5 * * * * root /usr/local/lib/snapshot/dequeue