cut column

ust · 01-08-2008, 11:05 AM

I have a file as below,

$vi myfile

aaa;20071217
bbb;20070404
ccc;20070254
"

I would like to have two script with requirement below

script 1 --> if I want to cut the column 9-12 of the first line , the output should be 1217 , can advise how to write a script to get the result ?

script 2 --> the result is 1217 , this is 17-Dec , if I would like the output is the format Dec 17 , how to write a script ?

ps. can I advise to write this two script , I hope this script only hv single line .

theNbomr · 01-08-2008, 11:23 AM

A perl one-liner...

Code:

perl -e 'while( <> ){ print substr( $_,8,4 ),"\n"; }' myfile

--- rod.

H_TeXMeX_H · 01-08-2008, 12:38 PM

Assume the filename is NewFile

For part 1 (this is at least 2x as fast as using Perl, use the 'time' program to check for yourself):

Code:

cut -b 9-12 NewFile

output is:

Code:

1217
0404
0254

For part 2 (haven't tested speed of this vs Perl, because I don't know Perl, this time my money is on Perl, but I could write a small C program to do this and it will be faster):

Code:

while read line; do echo $(echo $line | cut -b 9-10 | rev)$(echo $line | cut -b 11-12 | rev) | rev; done < NewFile

output is:

Code:

1712
0404
5402

colucix · 01-08-2008, 01:53 PM

Not checked for timing, but this other one-liner does all

Code:

gawk -F\; '{print $2}' myfile | date -f- +"%b %d"

ust · 01-08-2008, 07:14 PM

Quote:

Originally Posted by colucix

Not checked for timing, but this other one-liner does all

Code:

gawk -F\; '{print $2}' myfile | date -f- +"%b %d"

thx reply ,

this script should work fine ,

if the file format is as below , the 1200 is the time , can advise how to modify the script to get the same result ? Thx

aaa;200712171200
bbb;200704041200
ccc;200702541200

ust · 01-08-2008, 07:16 PM

Quote:

Originally Posted by colucix

Not checked for timing, but this other one-liner does all

Code:

gawk -F\; '{print $2}' myfile | date -f- +"%b %d"

thx reply ,

I tried the script , but it do not find the FIRST line of the line , what I want to get is the date in FIRST line , the second ,if the file format is as below , the 1200 is the time , can advise how to modify the script to get the same result ? Thx in advance.

aaa;200712171200
bbb;200704041200
ccc;200702541200

colucix · 01-08-2008, 08:33 PM

Quote:

Originally Posted by ust

I tried the script , but it do not find the FIRST line of the line , what I want to get is the date in FIRST line , the second ,if the file format is as below

Sorry, but I don't truly understand what you're saying: did you get an error when processing the first line of your file?

Regarding you're last example, you can simply extract a substring from the second field, like this

Code:

gawk -F\; '{print substr($2,1,8)}' myfile | date -f- +"%b %d"

Anyway you will get an error when processing the LAST line of your example, since the 54th of February has not been added to the calendar, yet!

ust · 01-08-2008, 09:05 PM

Quote:

Originally Posted by colucix

Sorry, but I don't truly understand what you're saying: did you get an error when processing the first line of your file?

Regarding you're last example, you can simply extract a substring from the second field, like this

Code:

gawk -F\; '{print substr($2,1,8)}' myfile | date -f- +"%b %d"

Anyway you will get an error when processing the LAST line of your example, since the 54th of February has not been added to the calendar, yet!

thx reply ,

your script works , but the result is as below,
Dec 17
Apr 04
Mar 26

what I want the result is Dec 17

thx.

ghostdog74 · 01-08-2008, 09:14 PM

Quote:

Originally Posted by ust

I have a file as below,

$vi myfile

aaa;20071217
bbb;20070404
ccc;20070254
"

I would like to have two script with requirement below

script 1 --> if I want to cut the column 9-12 of the first line , the output should be 1217 , can advise how to write a script to get the result ?

Code:

# cut -c9-12 file|head -1

Quote:

script 2 --> the result is 1217 , this is 17-Dec , if I would like the output is the format Dec 17 , how to write a script ?

ps. can I advise to write this two script , I hope this script only hv single line .

assuming you have GNU date

Code:

# date "+%b %d" -d `head -1 file|cut -d";" -f2`
Dec 17

ghostdog74 · 01-08-2008, 09:29 PM

Quote:

Originally Posted by H_TeXMeX_H

Code:

while read line; do echo $(echo $line | cut -b 9-10 | rev)$(echo $line | cut -b 11-12 | rev) | rev; done < NewFile

output is:

Code:

1712
0404
5402

Code:

# sed 's/.*\(..\)\(..\)$/\2\1/' file
1712
0404
5402

H_TeXMeX_H · 01-09-2008, 03:28 AM

Yeah, that is a better solution, and much faster too. Now, I'll have to look into how it works.