Differences

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--- bash_notes [2022/06/06 15:49] – [useful links] raju
+++ bash_notes [2022/11/08 20:40] – [what is the difference between "ls > dirlist 2>&1" and "ls 2>&1 > dirlist"?] raju
@@ Line 12: / Line 12: @@
 ==== documentation links ====
   * ignoredups, erasedups - https://www.gnu.org/software/bash/manual/html_node/Bash-Variables.html search for ignoredups .
+==== what is the difference between "ls > dirlist 2>&1" and "ls 2>&1 > dirlist"? ====
+The command
+<code>
+ls > dirlist 2>&1
+</code>
+directs both standard output (file descriptor 1) and standard error (file descriptor 2) to the file dirlist, while the command
+<code>
+ls 2>&1 > dirlist
+</code>
+directs only the standard output to file dirlist, because the standard error was made a copy of the standard output before the standard output was redirected to dirlist.
+To conclude, the order of redirections is significant.
+Ref:- https://www.gnu.org/software/bash/manual/html_node/Redirections.html -> 5th paragraph.
 ===== getopts =====
 ==== useful articles ====