# cat test.txt aaaaaaaaa bbbbbbbbb ccccccccc ddddddddd eeeeeeeee # # cat test.txt | tr '\n' ',' aaaaaaaaa,bbbbbbbbb,ccccccccc,ddddddddd,eeeeeeeee,# # #
# cat test.txt aaaaaaaaa bbbbbbbbb ccccccccc # # cat test.txt |tr -d '\n' aaaaaaaaabbbbbbbbbccccccccc# #
# cat test1.txt 1 2 3 4 5 a b c d e # cat test1.txt |tr -s ' ' 1 2 3 4 5 a b c d e #