Commands by leovailati

Commands by leovailati (5)

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Stream audio over ssh

This one doesn't need to convert to wav.
This is sample output - yours may be different.
6

ssh [user]@[address] "mpg321 -" < [file].mp3

leovailati · 2010-07-30 00:23:13 0
See udev at work

See how your system works with pendrives/mice/monitors/whatever-you-can-plug-in. Use cases: see on which /dev/... your peripherals are, find out if a specific udev rule is being applied correctly.
This is sample output - yours may be different.
20

udevadm monitor

leovailati · 2010-06-27 00:16:41 0
Use tagged vlans

Great for sysadmins! Don't forget to pass the vlan to your port in a manageable switch. After vconfig, you should use sudo ifconfig eth0.[VID] up Now the interface is up, you can use dhclient or ifconfig again to get an ip address.
This is sample output - yours may be different.
1

sudo vconfig add eth0 [VID]

leovailati · 2010-05-15 21:32:24 0
Change attributes of files so you can edit them

I had problems in Ubuntu while trying to edit /etc/resolv.conf, even with sudo I couldn't make any change. After a 2 minutes search on google I found this command. Hope someone finds it useful. It works like chmod, with + and - to denote which attributes are being added and which are being removed. See other attributes on man pages or on wikipedia http://en.wikipedia.org/wiki/Chattr
This is sample output - yours may be different.
1

sudo chattr -i <file that cannot be modified>

leovailati · 2010-03-25 03:14:34 0
Move itens from subdirectories to current directory

You WILL have problems if the files have the same name. Use cases: consolidate music library and unify photos (especially if your camera separates images by dates). After running the command and verifying if there was no name issues, you can use ls -d */ | sed -e 's/^/\"/g' -e 's/$/\"/g' | xargs rm -r to remove now empty subdirectories.
This is sample output - yours may be different.
-1

ls -d */* | sed -e 's/^/\"/g' -e 's/$/\"/g' | xargs mv -t $(pwd)

leovailati · 2010-03-01 23:43:26 2

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Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

copy/mkdir and automatically create parent directories

The --parents option will cause cp or mkdir to automatically create the parent directory structure. $mkdir --parents /one/two/three/dir will create /one, /one/two, and /one/two/three as needed before creating dir. cp will copy files with their full directory structure into the target directory with this option. Thanks to Peter Leung at: http://linuxcommando.blogspot.com/2007/11/use-of-parents-flag-in-mkdir-and-c.html which has good examples of usage.

find out how much space are occuipied by files smaller than 1024K

The command gives size of all files smaller than 1024k, this information, together with disk usage, can help determin file system parameter (e.g. block size) or storage device (e.g. SSD v.s. HDD). Note if you use awk instead of "cut| dc", you easily breach maximum allowed number of records in awk.

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Generic shell function for modifying files in-place

Some commands (such as sed and perl) have options to support in-place editing of files, but many commands do not. This shell function enables any command to change files in place. See the sample output for many examples. The function uses plain sh syntax and works with any POSIX shell or derivative, including zsh and bash.

Quick access to ASCII code of a key

Show errors in the kernel ring buffer

Much more useful then parsing syslog

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Rename files in batch

Find usb device in realtime

Using this command you can track a moment when usb device was attached.

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