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#!/usr/bin/env bash |
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|
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#### case |
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foo=a; case $foo in [0-9]) echo number;; [a-z]) echo letter;; esac |
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## stdout: letter |
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|
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#### case in subshell |
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# Hm this subhell has to know about the closing ) and stuff like that. |
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# case_clause is a compound_command, which is a command. And a subshell |
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# takes a compound_list, which is a list of terms, which has and_ors in them |
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# ... which eventually boils down to a command. |
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echo $(foo=a; case $foo in [0-9]) echo number;; [a-z]) echo letter;; esac) |
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## stdout: letter |
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|
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#### Command sub word part |
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# "The token shall not be delimited by the end of the substitution." |
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foo=FOO; echo $(echo $foo)bar$(echo $foo) |
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## stdout: FOObarFOO |
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|
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#### Backtick |
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foo=FOO; echo `echo $foo`bar`echo $foo` |
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## stdout: FOObarFOO |
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|
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#### Backtick 2 |
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echo `echo -n l; echo -n s` |
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## stdout: ls |
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|
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#### Nested backticks |
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# Inner `` are escaped! # Not sure how to do triple.. Seems like an unlikely |
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# use case. Not sure if I even want to support this! |
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echo X > $TMP/000000-first |
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echo `\`echo -n l; echo -n s\` $TMP | grep 000000-first` |
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## stdout: 000000-first |
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|
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#### Making command out of command sub should work |
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# Works in bash and dash! |
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$(echo ec)$(echo ho) split builtin |
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## stdout: split builtin |
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|
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#### Making keyword out of command sub should NOT work |
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# This doesn't work in bash or dash! Hm builtins are different than keywords / |
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# reserved words I guess. |
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# dash fails, but gives code 0 |
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$(echo f)$(echo or) i in a b c; do echo $i; done |
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echo status=$? |
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## stdout-json: "" |
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## status: 2 |
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## BUG dash stdout-json: "\nstatus=0\n" |
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## BUG dash status: 0 |
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## OK mksh status: 1 |
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|
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#### Command sub with here doc |
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echo $(<<EOF tac |
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one |
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two |
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EOF |
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) |
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## stdout: two one |
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|
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#### Here doc with pipeline |
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<<EOF tac | tr '\n' 'X' |
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one |
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two |
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EOF |
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## stdout-json: "twoXoneX" |
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|
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#### Command Sub word split |
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argv.py $(echo 'hi there') "$(echo 'hi there')" |
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## stdout: ['hi', 'there', 'hi there'] |
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|
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#### Command Sub trailing newline removed |
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s=$(python -c 'print "ab\ncd\n"') |
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argv.py "$s" |
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## stdout: ['ab\ncd'] |
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|
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#### Command Sub trailing whitespace not removed |
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s=$(python -c 'print "ab\ncd\n "') |
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argv.py "$s" |
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## stdout: ['ab\ncd\n '] |
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|
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#### Command Sub and exit code |
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# A command resets the exit code, but an assignment doesn't. |
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echo $(echo x; exit 33) |
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echo $? |
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x=$(echo x; exit 33) |
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echo $? |
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## STDOUT: |
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x |
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0 |
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33 |
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## END |
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|
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#### Command Sub in local sets exit code |
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# A command resets the exit code, but an assignment doesn't. |
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f() { |
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echo $(echo x; exit 33) |
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echo $? |
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local x=$(echo x; exit 33) |
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echo $? |
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} |
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f |
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## STDOUT: |
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x |
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0 |
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0 |
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## END |