英和和英

出典:『Wikipedia』 (2011/04/05 20:40 UTC 版)

英語による解説

引用

In computing, command substitution is a facility originally introduced in the Unix shells that allows a command to be run and its output to be pasted back on the command line as arguments to another command. Shells typically do this by creating a child process to run the first command with its standard output piped back to the shell, which reads that output, parsing it into words separated by whitespace. Because the shell can't know it has all the output from the child until the pipe closes or the child dies, it waits until then before it starts another child process to run the second command.