How can I change spaces to underscores and lowercase everything?
Question
I have a text file which contains:
Cycle code
Cycle month
Cycle year
Event type ID
Event ID
Network start time
I want to change this text so that when ever there is a space, I want to replace it with a _
. And after that, I want the characters to lower case letter like below:
cycle_code
cycle_month
cycle_year
event_type_id
event_id
network_start_time
How could I accomplish this?
Solution
Looking into sed documentation some more and following advice from the comments the following command should work.
sed -r {filehere} -e 's/[A-Z]/\L&/g;s/ /_/g' -i
OTHER TIPS
Another Perl method:
perl -pe 'y/A-Z /a-z_/' file
tr
alone works:
tr ' [:upper:]' '_[:lower:]' < file
There is a perl
tag in your question as well. So:
#!/usr/bin/perl
use strict; use warnings;
while (<DATA>) {
print join('_', split ' ', lc), "\n";
}
__DATA__
Cycle code
Cycle month
Cycle year
Event type ID
Event ID
Network start time
Or:
perl -i.bak -wple '$_ = join('_', split ' ', lc)' test.txt
sed "y/ABCDEFGHIJKLMNOPQRSTUVWXYZ /abcdefghijklmnopqrstuvwxyz_/" filename
Just use your shell, if you have Bash 4
while read -r line
do
line=${line,,} #change to lowercase
echo ${line// /_}
done < "file" > newfile
mv newfile file
With gawk:
awk '{$0=tolower($0);$1=$1}1' OFS="_" file
With Perl:
perl -ne 's/ +/_/g;print lc' file
With Python:
>>> f=open("file")
>>> for line in f:
... print '_'.join(line.split()).lower()
>>> f.close()
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