Bash, trim a "complicated" string to obtain a new string

Question

I have a txt file contains many strings(every string lies in a line). A typical string has this shape:

sno_Int-INT1_Exp-INT2_INT3.fits.fz_ovsc_rms_D4_D5_D6_D7_D8_D9

In the above string, "INT1", "INT2" and "INT3" are all integer types and their values might variant for each string in the text file, "D4 - 9" are double type(not fixed value also).

What I need to do is to change the above string to a new string like :

INT3_ovsc_rms_D4_D5_D6_D7_D8_D9

Can anybody tell me how to do it ?

Thanks!

How about not using Bash? Any preference among Ruby, Python, Perl? — John Zwinck, Mar 05 '14 at 12:57
@JohnZwinck, Thanks for comment. Currently, I prefer to do it in Bash since I'm in the middle of a project which was started with Bash. — user2740039, Mar 05 '14 at 13:01
@user2740039: Provide some real examples of input and output — anubhava, Mar 05 '14 at 13:03
@anubhava, sure, `INT3` is a runID, and I don't like to put all string because of two reasons : (1)it's not necessary; (2)there is no enough space to display it on a button of a website. — user2740039, Mar 05 '14 at 13:07
@anubhava, a real string is like `sno_Int-300_Exp-1000_1051.fits.fz_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14` — user2740039, Mar 05 '14 at 13:08

score 1 · Accepted Answer · answered Mar 05 '14 at 13:07

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#!/bin/bash

input=$1
left=${input%%.*}
right=${input#*.fz_}
int3=${left##*_}
output=${int3}_${right}

echo "${output}"

.

$ ./foo.sh sno_Int-INT1_Exp-INT2_INT3.fits.fz_ovsc_rms_D4_D5_D6_D7_D8_D9
INT3_ovsc_rms_D4_D5_D6_D7_D8_D9

$ ./foo.sh sno_Int-300_Exp-1000_1051.fits.fz_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14
1051_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14

Depending on your real input this might break horribly, though.

answered Mar 05 '14 at 13:07

Adrian Frühwirth

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"Depending on your real input this might break horribly" applies to most Bash seen in the wild.... – John Zwinck Mar 05 '14 at 13:08
@JohnZwinck Agreed, but one *can* write idiomatic and "beautiful" bash with proper error handling. It just doesn't happen very often ... – Adrian Frühwirth Mar 05 '14 at 13:10
@JohnZwinck, Thanks a lot for your contribution ! I like your solution not only it solved my asking but your code is very intuitive for me. Merci, :-) . – user2740039 Mar 05 '14 at 13:25

score 0 · Answer 2 · edited May 23 '17 at 10:31

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If you really want to do this in pure Bash, you'll need to split the string by setting IFS and then using read with a "here string". For details, see here: How do I split a string on a delimiter in Bash?

You will probably need to split it multiple times--once by underscore and then by dash, I guess.

edited May 23 '17 at 10:31

Community

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answered Mar 05 '14 at 13:04

John Zwinck

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score 0 · Answer 3 · answered Mar 05 '14 at 13:09

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If you don't mind awk:

echo sno_Int-INT1_Exp-INT2_INT3.fits.fz_ovsc_rms_D4_D5_D6_D7_D8_D9 | awk -F_ 'BEGIN{OFS="_"}{sub(/.fits.fz/,"",$4);print $4,$5,$6,$7,$8,$9,$10,$11,$12}'

INT3_ovsc_rms_D4_D5_D6_D7_D8_D9

answered Mar 05 '14 at 13:09

Mark Setchell

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Hi, Mark, thanks for your post. Your code run smoothly on my machine either. Unfortunately, I have issued the green icon of answer to somebody else... Thanks again ! – user2740039 Mar 05 '14 at 13:45

score 0 · Answer 4 · answered Mar 05 '14 at 13:18

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This awk should work:

s='1000_1051.fits.fz_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14'
awk -F'[_.]' 'NR==1{i3=$2;next} {printf "%s%s%s", i3, RS, $0}' RS='_ovsc_rms' <<< "$s"
1051_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14

answered Mar 05 '14 at 13:18

anubhava

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your code is cool. However, on my machine, I need to change the `$2` in the `{i3=$2}` to `$4` to get the same as yours(and I expected). Otherwise, what I obtained on my machine is : `Int-300_ovsc_rms_10.6_2.35_53.2_0_5.92_2.14` . – user2740039 Mar 05 '14 at 13:43

Bash, trim a "complicated" string to obtain a new string

4 Answers4