SHELL: line 1: syntax error: bad substitution
1
0
====
_
SHELL: line 1: 1: parameter not set
SHELL: line 1: 1: parameter not set or null
SHELL: line 1: 1: message1
SHELL: line 1: 1: message1
SHELL: line 1: 1: unset!
SHELL: line 1: 1: null or unset!
====
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_aaaa
_aaaa
_aaaa
_aaaa
_aaaa
_aaaa
====
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SHELL: line 1: f: parameter not set
SHELL: line 1: f: parameter not set or null
SHELL: line 1: f: message3
SHELL: line 1: f: message3
SHELL: line 1: f: unset!
SHELL: line 1: f: null or unset!
====
_
_
SHELL: line 1: f: parameter not set or null
_
SHELL: line 1: f: message4
_
SHELL: line 1: f: null or unset!
====
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_fff
_fff
_fff
_fff
_fff
_fff