Commands tagged random (98)

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Counts number of lines
Counts number of lines of code in *.h and *.cc files

Size (in bytes) of all RPM packages installed
This command will output the size of all RPM packages and string them together into one enormous addition command which will be calculated by the echo $(( ))

Split a tarball into multiple parts
Create a tar file in multiple parts if it's to large for a single disk, your filesystem, etc. Rejoin later with `cat .tar.*|tar xf -`

See The MAN page for the last command
This works in bash. The "!!:0" limits the argument to man to be only the first word of the last command. "!!:1" would be the second, etc.

show each new entry in system messages as a popup
It willl popup a message for each new entry in /var/log/messages found on the notify-send howto page on ubuntuforums.org. Posted here only because it is one of the favourites of mine.

Quick searching with less

Add directory to $PATH if it's not already there
Sometimes in a script you want to make sure that a directory is in the path, and add it in if it's not already there. In this example, $dir contains the new directory you want to add to the path if it's not already present. There are multiple ways to do this, but this one is a nice clean shell-internal approach. I based it on http://stackoverflow.com/a/1397020. You can also do it using tr to separate the path into lines and grep -x to look for exact matches, like this: $ if ! $(echo "$PATH" | tr ":" "\n" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://stackoverflow.com/a/5048977. Or replace the "echo | tr" part with a shell parameter expansion, like $ if ! $(echo "${PATH//:/$'\n'}" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://www.commandlinefu.com/commands/view/3209/. There are also other more regex-y ways to do it, but I find the ones listed here easiest to follow. Note some of this is specific to the bash shell.

Cut flv video from minute 19 to minute 20 using flvtool2
We should calculate the video duration to milliseconds, 1 minute = 60000 milliseconds

remote diff with side-by-side ordering.
more information: man sdiff

Virtualbox: setup hardware
where - memory 256 assign 256 Mb RAM - acpi on enable ACPI (mandatory if you use Winfog 2000 - ioapic off disable the IO APIC. Not useful if you use one CPU (on virtual machine or a 32 bit operative system). As ACPI, this switch is mandatory for Winbug 2000 - pae on enable the Phisical Address Extension how to use more than 4Gb of RAM on x86 CPU - hwvirtex on enables hardware virtualization extensions for microprocessors that have this feature (which should be also enabled in the BIOS of the motherboard) - nestedpaging on allows part of the processes of memory management hardware are made directly


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