I am trying to write a one line command to create 20 empty files with names extracted from a .txt file in another folder directory with the same txt extension.
I tried
for i in $(cat test.txt); do grep -w $i | touch $i.txt ; done
and
cat test.txt| while read line ; do grep $line ; touch $line.txt ; done
as well as
for filename in $(cat testfile.txt) ; do touch head -20 $filename.txt; done
It does not work. I do not know how to specify the 10 first words of the test.txt file.
Does this work for you?
while IFS= read -r i; do
touch "$i".txt
done < <(head -20 filename.txt)
done < <(head -20 filename.txt) and adding a -r to the read in case any of the filenames contain escapes. Arguably it should be while IFS= read -r i; do if we assume that any leading whitespace is intentional. I guess we should wait for clarification from the OP.
– steeldriver
Oct 21 at 15:03
Get first 20 words.
Using cut:
$ for i in $(cut -d ' ' -f1-20 a.txt); do touch $i.txt; done
(with mapfile):
$ mapfile -d ' ' -n 20 -t < a.txt; touch ${MAPFILE[@]/%/.txt}
(with awk):
$ awk '{for (i=1; i<=20; i++) {system("touch "$i".txt")}}' a.txt
(with shell parameter expansion):
$ a=($(<a.txt)); a=(${a[@]/%/.txt}); touch ${a[@]:0:19}
xargs command has --arg-file flag, which allows using arguments for a command you intend to run from file. Thus, you can do
xargs --arg-file=filenames.txt touch
If you want first 20 lines
head -n20 filenames.txt | xargs touch
Substitute tail instead of head for last 20 lines from file
for i in $(head test.txt); do touch $i.txt ; done? – mikewhatever Oct 21 at 13:50test.txtfile - the format matters e.g. whether there is one word per line, multiple words per line etc. – steeldriver Oct 21 at 13:55for i in $(head -n 20 test.txt); do touch $i.txt ; done, since you want 20 entries. – mikewhatever Oct 21 at 15:01