It works, but I have a Korn shell. Are you sure it will work with Korn shell?
This works in the Bourne shell and any shell derived from it: ksh88, ksh93, bash. See the man page and llok for "parameter expansion" to find out more about these constructs.
Of course what Scrutinizer has suggested is the preferred way to do it because it doesn't need to spawn a new process. To show you that many other (not as resource-preserving but still working) ways exist: use the basename utility. If it is provided a second argument it interprets this as extension and eventually cuts off this from the end of a filename:
Hi,
My knowledge about sed is limited but I have a problem that I think can be solved with sed.
I have a variable in a shell script that stores a lot of path/filenames and the delimitter between them is a space (they all exist on the same line). One part of the filename is the file creation... (4 Replies)
I would like to remove characters from column 7 so that from an input file looking like this:
>HWI-EAS422_12:4:1:69:89 GGTTTAAATATTGCACAAAAGGTATAGAGCGT U0 1 0 0 ref_chr8.fa 6527777 F DD
I get something like that in an output file:
... (13 Replies)
How do you truncate specific parts of a string.
Example:
1 This is the string
Goal:
This is the string
As you can see I'm trying to simply remove the first two characters of the string the number one and the space between the one and the word "this."
Your help is appreciated.
... (8 Replies)
hi everybody..
I have a string like :
abcd:efgh
xxyy:yyxx
ssddf:kjlioi
ghtyu:jkksk
nhjkk:heuiiue
please tell me how i can display only the characters after ":" in the output
the output should be :
efgh
yyxx
kjlioi
jkksk
heuiiue
please give quick reply.. its urgent..!! (6 Replies)
I know how to do produce this:
string01
string02
string03
several different ways.
But how do I do produce this (without getting lost in recursion):
string01morestring100yetmore10
string02morestring101yetmore20
string03morestring102yetmore30
...... (2 Replies)
Hello, let's say I have this string:
string1="A\nB\nC D E\nFG\nH";
How can I split it so as to take every string separated with '\n' separately?
For example, as for $string1, it would be split into
string1_part1="A"
string1_part2="B"
string1_part3="C D E"
string1_part4="FG"... (5 Replies)
Hi there,
I have an output from a command like this
# ypcat -k netgroup.byuser| grep steven
steven.* users_main,users_sysadmin,users_global,users_backup_team
and wanted to pull the 'users' netgroups returned into a perl array, that will look like this
users_main... (2 Replies)
Hi Guys,
writing a small shell script, i need to convert parts of a string to "Hex". The problem is that it is not the full string that needs to be converted.
I think it's best to show an example:
$astring = "xxxxxx ABC+10+##########+DEF xxxx"
This is only an example to show how the... (9 Replies)
I have number in file which contains date and serial number:
2013101000.
The last two digits are serial number (00). So maximum of serial number is 100.
After reaching 100 it becomes 00 with incrementing 10 which is day with max 31.
after reaching 31 it becomes 00 and increments 10... (31 Replies)
Discussion started by: Natalie
31 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)