Commands using cd (215)

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Null a file with sudo

Query ip pools based on successive netnames via whois
Useful if you f.i. want to block/allow all connections from a certain provider which uses successive netnames for his ip blocks. In this example I used the german Deutsche Telekom which has DTAG-DIAL followed by a number as netname for the dial in pools. There are - as always ;) - different ways to do this. If you have seq available you can use $ net=DTAG-DIAL ; for i in `seq 1 30`; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; done or without seq you can use bash brace expansion $ net=DTAG-DIAL ; for i in {1..30}; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; done or if you like while better than for use something like $ net=DTAG-DIAL ; i=1 ; while true ; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; test $i = 30 && break ; i=$(expr $i + 1) ; done and so on.

Press ctrl+r in a bash shell and type a few letters of a previous command
In the sample output, I pressed ctrl+r and typed the letters las. I can't imagine how much typing this has saved me.

Alias for quick command-line volume set (works also remotely via SSH)
If you're addicted to command-line solutions of ordinary actions or if you just want to set your volume from bed via mobile phone SSH, you can set this alias and use it as $ setvol 50 for setting volume on 50% gain Works only with ALSA, tested on Ubuntu 8.10. Give me some info about your experience. TIP: Try aslo command "mute" to toggle mute/unmute sound. But I don't know if this works on all distros.

Follow the most recently updated log files
This command finds the 5 (-n5) most frequently updated logs in /var/log, and then does a multifile tail follow of those log files. Alternately, you can do this to follow a specific list of log files: sudo tail -n0 -f /var/log/{messages,secure,cron,cups/error_log}

sed edit-in-place using -a option instead of -i option (no tmp file created)
does the -i option open a tmp file? this method does not.

Get MAC address

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

view all lines without comments.

convert wav files to flac
cd to the folder containing the wav files, then convert them all to flac. yeah baby! in ubuntu, to get the flac program just: sudo apt-get install flac flac file input formats are wav, aiff, raw, flac, oga and ogg


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