I have csv data like:
a,b,c,d,e,f,g,h
I want this data in a list, one letter in each line. Is it possible is shell script? I have tried to extract each letter using cut command as shown below:
less list.txt | cut -d"," -f?
The command is working but the problem here is the number of fields is unknown. I have to place this command in a loop and iterate on the list so that I can extract the values one-by-one a redirect them to another file.
You could use the tr command to transform each "," into a newline.
cat list.txt | tr "," "\n"
From then you can output each line wherever you want using a while read loop
cat list.txt | tr "," "\n" | while read LINE
do
echo "$LINE" >> ~/wherever/you/want
done
Or ...
while read LINE
do
echo "$LINE" >> ~/wherever/you/want
done <<< "$(cat list.txt | tr "," "\n")"
Either works.
You can use sed for this:
sed "s/,/\n/g" list.txt
Output
a
b
c
d
e
f
sed -r -s -u -l10000 --posix -e "s/,/\n/g". Still pointless though.
-e is that if the sed script ever needs to start with a - (which may or may not actually be possible) you won't need to remember to add -e and if you ever want to add a second script to the command you can just add -e <script> to the end without needing to go add -e before the first script. That said it doesn't really matter.-. My point was that it is a single script that doesn't begin like that. I understand when -e can be useful, just like all the flags in my other comment "can" be useful, just not in this case.-r should be there so you don't have to remember to add it if you start using ERE. But OP is not and neither of them is needed.Yes, you can use cut. The key point is the usage of --output-delimiter. If you set it as new line, everything works:
cut -d',' --output-delimiter=$'\n' -f1- file
Note also two facts:
-f1- to print from the first field up to the last one. The n- syntax means: from the n-th field up to the end.$'\n' because \n alone would print literal \n instead of real new lines.$ echo "a,b,c,d,e,f,g,h" | cut -d',' --output-delimiter=$'\n' -f1-
a
b
c
d
e
f
g
h
From man cut:
--output-delimiter=STRING
use STRING as the output delimiter the default is to use the input delimiter
less. More conventional would becut file,cut < file, or, if you really want to use a pipe,cat file | cut. If less did its usual job, you'd have to keep hitting the spacebar to finish, but actually, it notices that standard output is not your screen, and basically turns itself intocatfor you.