My curiosity got the better of me. I created two files with a million lines each. One file consists of lines that never require any substitution. The other of lines that always require substitution. I then tested the solutions on each.
$ time sed 's/|0*/|/' data-without-0 > /dev/null
real 0m2.006s
user 0m1.898s
sys 0m0.072s
$ time sed 's/^\([^|]*|\)00*/\1/' data-without-0 > /dev/null
real 0m0.942s
user 0m0.863s
sys 0m0.066s
Substitution necessary:
Code:
$ time sed 's/|0*/|/' data-with-0 > /dev/null
real 0m2.136s
user 0m2.031s
sys 0m0.077s
$ time sed 's/^\([^|]*|\)00*/\1/' data-with-0 > /dev/null
real 0m12.654s
user 0m12.320s
sys 0m0.137s
While the more complicated solution shows some improvement when no substition is required at all, about 1 second per million lines, it exhibits a much larger degration if substitution is required by all lines. Based on my brief testing (insert all the usual caveats about benchmarking here ), I would not choose your approach unless the data set is massive AND there are few lines within it requiring modification.
How do I trim the leading zeroes, and (+,-) in the currency field ?
I have a text file.
Your bill of +00002780.96 for a/c no. 25287324 is due on 11-06.
Your bill of +00422270.48 for a/c no. 28931373 is due on 11-06.
I want the O/P file to be like.
Your bill of 2780.96 for a/c no. 25287324... (22 Replies)
Hello, I am (trying) to write a script that will check to see how many users are logged on to my machine, and if that number is more than 60 I need to kill off all the oldest sessions that are over 60. So far I have been able to check how many users are on and now I am at the part where I have to... (3 Replies)
Helo ,
I m writing small module of c.on RHEL 4
I have one buffer (for e.g. buffer = "002"
now I want to check whethere buffer contains leading zeroes and if it contains
leading zeroes then I want to remove all leading zeroes
( i.e. if buffer = "002" then I want to make buffer = "2")
how... (1 Reply)
Hello and thx for reading this
I'm using sed to remove only the leading spaces in a file
bash-280R# cat foofile
some text
some text
some text
some text
some text
bash-280R#
bash-280R# sed 's/^ *//' foofile > foofile.use
bash-280R# cat foofile.use
some text
some text
some text... (6 Replies)
Hi,
I need add leading zeroes to a field in a file based on the character count. The field can be of 1 character to 6 character length. I need to make the field 14bytes.
eg:
8351,20,1
8351,234,6
8351,2,0
8351,1234,2
8351,123456,1
8351,12345,2
This should become.
... (3 Replies)
I have th following file
0000000011
0000000001
0000000231
0000000001
0000000022
noow when i run the following command
sed 's/^0+//g' file name
I receive the same output and the leading zeroes are not removed from the file . Please let me know how to achieve... (4 Replies)
I have the following script that renames filenames like:
blah_bleh_91_2011-09-26_00.05.43AM.xls
and transforms it in:
91_20110926_000543_3_blih.xls
for a in *.xls;
do
b="$(echo "${a}" | cut -d '_' -f4)"
dia=`echo ${b} | cut -c9-10`
mes=`echo ${b} | cut -c6-7`
anio=`echo ${b} | cut -c1-4`... (4 Replies)
Need help. I tried using an awk command to pad zeroes. Unfortunately, the "|" pipe delimited character is gone when I tried to write the records to another file.
awk -F \| ' {$1=sprintf("%06s", $1); print $0}' $CUSTFINAL2 > $CUSTFINAL3
BEFORE
"KEYRECORD"|"SA ID"|"PER ID"|"SP ID"|"ACCT... (3 Replies)
I have a requirement to replace "\" with "/" in only the 2nd field of the input file which has 2 fields. The field delimiter is "|"
Sample records from input file:
1\23|\tmp\user
mn\wer|\home\temp
Expected output:
1\23|/tmp/user
mn\wer|/home/temp
I used
sed 's/\\/\//g'
... (2 Replies)
Hi again
I have an xml file and want to remove the leading white space as it causes me issues later in my script
I see sed is possible but cant seem to get it to work
I tried
sed 's/^ *//' file.xml
output
<xn:VsDataContainer id="1U104799" modifier="update">
... (10 Replies)
Discussion started by: aniquebmx
10 Replies
LEARN ABOUT PLAN9
tail
TAIL(1) General Commands Manual TAIL(1)NAME
tail - deliver the last part of a file
SYNOPSIS
tail [ +-number[lbc][rf] ] [ file ]
tail [ -fr ] [ -n nlines ] [ -c ncharacters ] [ file ]
DESCRIPTION
Tail copies the named file to the standard output beginning at a designated place. If no file is named, the standard input is copied.
Copying begins at position +number measured from the beginning, or -number from the end of the input. Number is counted in lines, 1K
blocks or characters, according to the appended flag or Default is -10l (ten ell).
The further flag causes tail to print lines from the end of the file in reverse order; (follow) causes tail, after printing to the end, to
keep watch and print further data as it appears.
The second syntax is that promulgated by POSIX, where the numbers rather than the options are signed.
EXAMPLES
tail file
Print the last 10 lines of a file.
tail +0f file
Print a file, and continue to watch data accumulate as it grows.
sed 10q file
Print the first 10 lines of a file.
SOURCE
/sys/src/cmd/tail.c
BUGS
Tails relative to the end of the file are treasured up in a buffer, and thus are limited in length.
According to custom, option +number counts lines from 1, and counts blocks and characters from 0.
TAIL(1)
10-04-2010
), I would not choose your approach unless the data set is massive AND there are few lines within it requiring modification.