이 명령은 무엇을 합니까?

이와 같은 명령이 있는 경우 각 부분을 시도하여 해당 명령이 수행하는 작업을 확인하십시오.

예를 들어, 다음을 각각 실행하여 수행되는 작업을 확인하세요.

cat telephone.txt
cat telephone.txt | cat
cat telephone.txt | cat | cat
cat telephone.txt | cat | cat | sed -e "s/t/T/"
cat telephone.txt | cat | cat | sed -e "s/t/T/" | tee cible
cat telephone.txt | cat | cat | sed -e "s/t/T/" | tee cible | wc -l

이 작업을 수행하면 다음이 표시됩니다.

cat telephone.txt <-- reads file
cat <-- reads stdin and prints to stdout (from comments)
cat <-- reads stdin and prints to stdout (from comments)
sed -e "s/t/T/" <-- replaces the first lower case t on each line with an upper case T
tee cible <-- reads stdin and prints to stdout and also writes it to a file called "cible"
wc -l <-- counts the lines of stdout from above