Commands by akg240

Commands by akg240 (3)

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Floating point power p of x

One pipe less. Show Sample Output
This is sample output - yours may be different.
```
1.41421356237309504878
```
1

bc -l <<< "x=2; p=0.5; e(l(x)*p)"

akg240 · 2009-09-04 15:50:48 2
floating point operations in shell scripts

-l auto-selects many more digits (but you can round/truncate in your head, right) plus it loads a few math functions like sin(). Show Sample Output
This is sample output - yours may be different.
```
.56464247339503535720
```
3

bc -l <<< s(3/5)

akg240 · 2009-09-02 15:41:39 3
list all hd partitions

Only one command and not dependant on full read access to the devices. Show Sample Output
This is sample output - yours may be different.
```
sda1
sda2
sda3
sda5
sda6
sda7
sda8
sda9
sdb1
```
3

awk '/d.[0-9]/{print $4}' /proc/partitions

akg240 · 2009-09-02 15:26:03 1

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tar pipe to copy files, alternate to cp -Ra

uses tar to dump files from /orignl/path to /dst/dir. i find tar's out more readable than cp, and it doesn't mess with modified dates.

Numeric zero padding file rename

This uses Perl's rename utility (you may have to call it as prename on your box) and won't choke on spaces or other characters in filenames. It will also zero pad a number even in filenames like "vacation-4.jpg".

Get AWS temporary credentials ready to export based on a MFA virtual appliance

You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

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Lists architecture of installed RPMs

Lists all installed RPM packages with name and architecture, which is useful to check for compability packages (+ required i386 packages) on a 64bit system.

List all files ever added in git repository

Check ps output to see if file is running, if not start it

This comes in handy if you have daemons/programs that have potential issues and stop/disappear, etc., can be run in cron to ensure that a program remains up no matter what. Be advised though, if a program did core out, you'd likely want to know why (gdb) so use with caution on production machines.

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" }

Gets the X11 Screen resolution

Requires xrandr, grep and, sed.

Insert commas to make reading numbers easier in the output of ls

This modifies the output of ls so that the file size has commas every three digits. It makes room for the commas by destructively eating any characters to the left of the size, which is probably okay since that's just the "group". Note that I did not write this, I merely cleaned it up and shortened it with extended regular expressions. The original shell script, entitled "sl", came with this description: : ' : For tired eyes (sigh), do an ls -lF plus whatever other flags you give : but expand the file size with commas every 3 digits. Really helps me : distinguish megabytes from hundreds of kbytes... : : Corey Satten, corey@cac.washington.edu, 11/8/89 : ' Of course, some may suggest that fancy new "human friendly" options, like "ls -Shrl", have made Corey's script obsolete. They are probably right. Yet, at times, still I find it handy. The new-fangled "human-readable" numbers can be annoying when I have to glance at the letter at the end to figure out what order of magnitude is even being talked about. (There's a big difference between 386M and 386P!). But with this nifty script, the number itself acts like a histogram, a quick visual indicator of "bigness" for tired eyes. :-)

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