Checking and replacing first line in text file, one-liner?
Hello,
I'm looking to check only the first line of a file to see if it is a format string, like
if the first line is anything else, insert the above string.
I'd appreciate a one liner as I'm putting this command inside of a
so far I'm hacking awk that looks like
which correctly detects if the format string is there or not but can't seem to figure out how to get awk to redirect the pipe to insert the format string?
I must remove hex characters 0A and 0D from several fields within an MS Access Table. Since I don't think it can be done in Access, I am trying here.
I am exporting a Table from Access (must be fixed length fields, I think, for my idea to work here) into a text format.
I then want to run a... (2 Replies)
Hello,
I have the following report (report.txt) file (see attached).
I would like to check the file and if the field is error, then showing error message at output.
1. In the report, 1st, 2st and 3nd line can be ignore to check
2. start to check line 4 (each field use "," to split
- 1st... (1 Reply)
Hi
I need a perl onliner to delete a line in a file starting with few words.
Example
file.txt
----------
my name is don
I live in London
I am woking as engineer
I want to delete a line starting with 'I live in' using perl oneliner and in place edit with out temporary files
Thanks... (2 Replies)
can someone help me translate the following command, from:
/usr/bin/awk "/^$TOFDAYM $TOFDAYD /,0" $LOGFILE
to something like
perl -e .....
basically, i want to use perl to do awk functions within a shell script. i want to do the above awk, using perl.
any suggestions? (9 Replies)
I have file like this
"copy table_name from filea.txt on node replace delimiter '|';"
"copy table_name from fileb.txt on node replace delimiter '|';"
"copy table_name from filec.txt on node replace delimiter'|';"
"copy table_name from filee.txt on node replace delimiter '|';"
"copy... (1 Reply)
Hi
I need to write a Perl script that the file given as first argument of the command line that will find all occurrences of the string given as the third argument of the command line and replace with the string given as the fourth argument. Name newfound file is specified as the second... (3 Replies)
Is it possible to replace a line of text within a file while it's closed with a single command or a script? Please show me an example or point me to a webpage that shows an example. The file has this line of text:
LoginGraceTime 100
I want to replace it with the following:
... (2 Replies)
Hi,
I've got this output:
# cat test2.txt
TM1ITP1-TMNLSTP1 SLC00=0,SLC01=0,SLC02=0,SLC03=0
if I just use cat test2.txt | tr "," "\n" I'll end up very near to what I'm trying to achieve:
TM1ITP1-TMNLSTP1 SLC00=0
SLC01=0
SLC02=0
SLC03=0
But how can i eventually add the term... (1 Reply)
Hi
I want to replace time stamp in the following line
PROCNAME.Merge.exchMon.CODE.T_QSTART 08:45 read
assuming the new time stamp is 09:45 ; the line is getting replaced as below
:45 read
I'm trying to use the perl one liner in bash script
perl -pi... (4 Replies)
Discussion started by: charlie87
4 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)