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--- bash:output:check_exit_status [2021/01/26 14:49] – created peter
+++ bash:output:check_exit_status [2021/01/26 14:58] (current) – [Exit Status from a piped command - using PIPESTATUS] peter
@@ Line 1: / Line 1: @@
 ====== BASH - Output - Check Exit Status ======
+To get the exit status, you use the special parameter **$?** after running the command:
+<code bash>
+command
+status=$?
+</code>
+----
+===== Check exit status =====
+If you don't actually want to store the exit status, but simply want to take an action upon success or failure, just use if:
+<code bash>
+if command; then
+    printf "it succeeded\n"
+else
+    printf "it failed\n"
+fi
+</code>
+----
+===== Exit Status from a piped command - use PIPESTATUS =====
+What if you want the exit status of one command from a pipeline?
+If you want the last command's status, no problem -- it's in **$?** just like before.
+If you want some other command's status, use the PIPESTATUS array.
+<WRAP info>
+**NOTE:**  This is BASH only.
+In the case of Zsh, it's lower-cased pipestatus).
+</WRAP>
+Say you want the exit status of grep in the following:
+<code bash>
+grep foo somelogfile | head -5
+status=${PIPESTATUS[0]}
+</code>
+----
+Bash 3.0 added a **pipefail** option as well, which can be used if you simply want to take action upon failure of the grep:
+<code bash>
+set -o pipefail
+if ! grep foo somelogfile | head -5; then
+    printf "uh oh\n"
+fi
+</code>
+----