Greg Donald : Author, software maker, RC airplane enthusiast, player of strung instruments, bibliophile.

How to filter out Bash arguments

Ever want to know how to drop an argument (and value), --dir in this case, from a Bash script? Someone from my local LUG asked how to do it and this is what I came up with: Fun ;) #!/usr/bin/env bash args=("$@") myargs=() nextarg=-1 for ((i=0; i<$#; i++)) { if [ $nextarg == $i ]; then continue; fi case ${args[$i]} in --dir) nextarg=$((i+1)) ;; *) myargs+="${args[$i]} " esac } echo $myargs ./remove_dir.bash --dir foo --bar baz --bar baz

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bash (3)

MongoDB Data Durability

It doesn't seem you can lose data even when you might otherwise expect to ;) I setup a small replica set using mongod --fork --logpath a.log --smallfiles --oplogSize 50 --port 27001 --dbpath data/z1 --replSet z mongod --fork --logpath b.log --smallfiles --oplogSize 50 --port 27002 --dbpath data/z2 --replSet z mongod --fork --logpath c.log --smallfiles --oplogSize 50 --port 27003 --dbpath data/z3 --replSet z And initalized it: > rs.initiate( { _id:'z', members:[ { _id:1, host:'localhost:27001' }, { _id:2, host:'localhost:27002' }, { _id:3, host:'localhost:27003' } ] } ); Then I killed all three processes: kill -9 25542 25496 25483 Next I brought one of them back up mongod --fork --logpath c.log --smallfiles --oplogSize 50 --port 27003 --dbpath data/z3 and inserted a doc > db.foo.insert({a:1}) Then I killed that process kill -9 25885 and brought the replica set back online using mongod --for

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mongodb (1)

My bashrc file

alias ls='ls -ah --color=always' alias ll='ls -lavh --color=always' alias cp='cp -i' alias vi='/usr/bin/emacs' alias ..='cd ..' alias ...='cd ../..'

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bash (3)

PostgreSQL Sequence Updates

I had a problem with PostgreSQL pgdump recently. My setval() calls were all set to '1'. I whipped up this quick script to fix things: #!/usr/bin/env python DB_NAME = 'my_db' from subprocess import Popen, PIPE import re exclude = [ 'tablename', 'rows' ] tp = re.compile( '[^a-z_]' ) ts = Popen( [ "/usr/bin/psql", DB_NAME, "-c SELECT tablename FROM pg_tables WHERE tablename NOT LIKE 'pg_%' AND tablename NOT LIKE 'sql_%' ORDER BY tablename" ], stdout=PIPE ).communicate()[ 0 ].split( ' ' ) tables = [] for t in ts: t = tp.sub( '', t ) if len( t ) == 0 or t in exclude: continue tables.append( t ) for t in tables: sql = "SELECT pg_catalog.setval( pg_get_serial_sequence( '%s', 'id' ), ( SELECT MAX( id ) FROM %s ) + 1 );" % ( t, t ) print Popen( [ "/usr/bin/psql", DB_NAME, "-c %s" % sql ], stdout=PIPE ).communicate()[ 0 ]

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postgresql (3) python (2)

Mutt Configuration

# basic .muttrc for use with Gmail # Change the following six lines to match your Gmail account details set imap_user = "username@gmail.com" set imap_pass = "" set smtp_url = "smtp://username@smtp.gmail.com:587/" set smtp_pass = "" set from = "username@gmail.com" set realname = "Firstname Lastname" # # # Change the following line to a different editor you prefer. set editor = 'vim + -c "set textwidth=72" -c "set wrap"'

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mutt (1) gmail (1)

Debian rc.local howto

If you're using a flavor of *nix that has an rc.local file, and then you start using Debian GNU/Linux, you might be wondering where your rc.local file is. Quite simply, it's not there. Here's how to add it. Create a new file named /etc/init.d/local like this: #!/bin/sh # put startup stuff here Make the file executable: chmod 755 /etc/init.d/local Add it to startup: update-rc.d local defaults 80 You should be seeing something like this: Adding system startup for /etc/init.d/local ... /etc/rc0.d/K80local -> ../init.d/local /etc/rc1.d/K80local -> ../init.d/local /etc/rc6.d/K80local -> ../init.d/local /etc/rc2.d/S80local -> ../init.d/local /etc/rc3.d/S80local -> ../init.d/local /etc/rc4.d/S80local -> ../init.d/local /etc/rc5.d/S80local -> ../init.d/local

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linux (9) debian (5)

Debian Games

Here's a command to install lots of games on your Debian box: yes | \ for x in `apt-cache search game \ | sort \ | awk 'BEGIN { FS = " - " } { print $1 }'`; do \ apt-get install $x; \ done

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debian (5) game (5)