Linux Bash shell one practice : array if else

標籤：

shell practice 1
1.require
A B C D
1 2 3 4
5 6 7 8
3 5 8 0
1 2 4 3
after handling:
T A B C D
A 1 2 3 4
B 5 6 7 8
C 3 5 8 0
D 1 2 4 3

1.first need read the first line as an array.
then append the element in the proper position for file;

 

oldifs=$IFSIFS=$‘\n‘;counter=0;cols=‘‘for line in $(cat test.txt);doif [ $counter -eq 0 ]; thenIFS=$‘ ‘read -a cols <<< "$line";echo ‘T ‘ $line > test_new.txt;IFS=$‘\n‘;else echo "${cols[counter-1]} " $line>>test_new.txt;filet counter++;done;cat test_new.txt;IFS=$oldifs;

Linux Bash shell one practice : array if else