draw `vmstat ` data using gnuplot

This pipeline will find, sort and display all files based on mtime. This could be done with find | xargs, but the find | xargs pipeline will not produce correct results if the results of find are greater than xargs command line buffer. If the xargs buffer fills, xargs processes the find results in more than one batch which is not compatible with sorting.

Note the "-print0" on find and "-0" switch for perl. This is the equivalent of using xargs. Don't you love perl?

Note that this pipeline can be easily modified to any data produced by perl's stat operator. eg, you could sort on size, hard links, creation time, etc. Look at stat and just change the '9' to what you want. Changing the '9' to a '7' for example will sort by file size. A '3' sorts by number of links....

Use head and tail at the end of the pipeline to get oldest files or most recent. Use awk or perl -wnla for further processing. Since there is a tab between the two fields, it is very easy to process.

I have a directory containing log files. This command delete all but the 5 latest logs. Here is how it works:

* The ls -t command list all files with the latest ones at the top

* The awk's expression means: for those lines greater than 5, delete.

This will calculate a running standard deviation in one pass and should never have the possibility for overflow that can happen with other implementations. I suppose there is a potential for underflow in the corner case where the deltas are small or the values themselves are small.

This command displays a list of lines that are longer than 72 characters. I use this command to identify those lines in my scripts and cut them short the way I like it.

Removes trailing newline; colon becomes record separator and newline becomes field separator, only the first field is ever printed. Replaces empty entries with $PWD. Also prepend relative directories (like ".") with the current directory ($PWD). Can change PWD with env(1) to get tricky in (non-Bourne) scripts.

This is really fast :)

204753

real 0m0.191s

user 0m0.068s

sys 0m0.116s

Checks the Gmail ATOM feed for your account, parses it and outputs a list of unread messages.

For some reason sed gets stuck on OS X, so here's a Perl version for the Mac:

If you want to see the name of the last person, who added a message to the conversation, change the greediness of the operators like this:

Does not require input to function or complete. Number of iterations controlled by shell variable $NUM.

Have wc work on each file then add up the total with awk; get a 43% speed increase on RHEL over using "-exec cat|wc -l" and a 67% increase on my Ubuntu laptop (this is with 10MB of data in 767 files).

needs no GNU tools, as far as I see it

saves one command. Needs GNU grep though :-(

The grep switches eliminate the need for awk and sed. Modifying vim with -p will show all files in separate tabs, -o in separate vim windows. Just wish it didn't hose my terminal once I exit vim!!

This will drop you into vim to edit all files that contain your grep string.

Check which files are opened by Firefox then sort by largest size (in MB). You can see all files opened by just replacing grep to "/". Useful if you'd like to debug and check which extensions or files are taking too much memory resources in Firefox.

( IFS=:; for i in $PATH; do echo $i; done; )

echo $PATH|sed -e 's/:/\n/g' # but the tr one is even better of course

echo $PATH|xargs -d: -i echo {} # but this comes up with an extra blank line; can't figure out why and don't have the time :(

echo $PATH|cut -d: --output-delimiter='

' -f1-99 # note -- you have to hit ENTER after the first QUOTE, then type the second one. Sneaky, huh?

echo $PATH | perl -l -0x3a -pe 1 # same darn extra new line; again no time to investigate

echo $PATH|perl -pe 's/:/\n/g' # too obvious; clearly I'm running out of ideas :-)

More of the same but with more elaborate perl-fu :-)

?Cat and grep? You can use only grep ("grep \. filename"). Better option is awk.

Breaks down and numbers each line and it's fields. This is really useful when you are going to parse something with awk but aren't sure exactly where to start.

converts any number on the 'stdin' to SI notation. My version limits to 3 digits of precious (working with 10% resistors).

the f is for file and - stdout, This way little shorter.

I Like copy-directory function It does the job but looks like SH**, and this doesn't understand folders with whitespaces and can only handle full path, but otherwise fine,

function copy-directory () { ; FrDir="$(echo $1 | sed 's:/: :g' | awk '/ / {print $NF}')" ; SiZe="$(du -sb $1 | awk '{print $1}')" ; (cd $1 ; cd .. ; tar c $FrDir/ )|pv -s $SiZe|(cd $2 ; tar x ) ; }

grep -o puts each occurrence in a separate line

grep's -c outputs how may matches there are for a given file as "file:N", cut takes the N's and awk does the sum.