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--- bash [2020/08/12 17:14] – created shawn
+++ bash [2020/08/12 19:07] (current) – [Functions] Adds tips shawn
@@ Line 1: / Line 1: @@
+''#!/usr/bin/env bash'' - Use ''bash'' found in the environment path. Protects against not knowing where user's ''bash'' is installed.
 ====== set options ======
+''set options -xeuo''
 Commonly used options:
-  * -x:  turns on debug output, logging each command as it is executed
+  * ''-x'':  turns on debug output, logging each command as it is executed
-  * -e:  causes the script to exit on most command failures (non-zero exit codes)
+  * ''-e'':  causes the script to exit on most command failures (non-zero exit codes)
-  * -u:  treats unset variables and parameters other than the special parameters @ or * as an error when performing parameter expansion
+  * ''-u'':  treats unset variables and parameters other than the special parameters @ or * as an error when performing parameter expansion
-  * -o pipefail: causes the script to exit if a command in a pipeline fails
+  * ''-o pipefail'': causes the script to exit if a command in a pipeline fails
-  * use a+ to unset them if necessary
+  * use a + to unset them if necessary
 Many more options available:  https://www.gnu.org/software/bash/manual/html_node/The-Set-Builtin.html
@@ Line 14: / Line 18: @@
 ====== Variables ======
-  * $@ - All of the arguments as individual strings
+  * ''$@'' - All of the arguments as individual strings
-  * "$*" - All of the arguments as a single string
+  * ''"$*"'' - All of the arguments as a single string
-  * $# - The number of arguments
+  * ''$#'' - The number of arguments
-  * $1..n - Where n is an integer, the nth argument in the list
+  * ''$1..n'' - Where n is an integer, the nth argument in the list
-  * $0 - The command name
+  * ''$0'' - The command name
-  * $? - The last exit code
+  * ''$?'' - The last exit code
-  * $IFS - Internal/input field separator (defaults to combo of space, newline and tab)
+  * ''$IFS'' - Internal/input field separator (defaults to combo of space, newline and tab)
+====== Functions ======
+Declaring a function (needs to happen before use):
+''function <function_name> { ... do things ... }''
+- or -
+''<function_name>() { ... do things ... }''
+  * Nothing ever goes inside parentheses.
+  * Passed parameters can be accessed with ''$1''..''$n''.
+====== Tips ======
+  * [[https://stackoverflow.com/a/16496491|Use getopts to parse commandline options]].