Hello cola,

Following are the answers for your queries.

Code:

cat  Input_file
abcdef
test test test1
test2 asajndjad
dwjfewygfwkcm wdjcwcnwnc

Now if want to look for string test in above Input_file then example of UUOC is as follows.

Code:

cat Input_file | grep "test"
test test test1
test2 asajndjad

Above will read the Input_file by catcommand then it will push the standard output of this command as standard input to next grepcommand(that's why pipe|is used here) which will then read file and search for string testthen. So point here is unnecessarily we are using catwhen grepitself is capable to read Input_file from itself. So by directly using grephere to read and search Input_file we could save sometime(depending upon you Input_file size) and processes too.

Now following is the example of grepwhich is capable of reading the Input_file by itself and search a string too.

Code:

grep "test"  Input_file
test test test1
test2 asajndjad

I hope this helps you.

Thanks,
R. Singh