| 1 | ## compare_shells: bash-4.4 zsh
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| 2 |
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| 3 | # mksh and dash don't support it
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| 4 |
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| 5 | #### Process sub input
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| 6 | f=_tmp/process-sub.txt
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| 7 | { echo 1; echo 2; echo 3; } > $f
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| 8 | cat <(head -n 2 $f) <(tail -n 2 $f)
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| 9 | ## STDOUT:
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| 10 | 1
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| 11 | 2
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| 12 | 2
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| 13 | 3
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| 14 | ## END
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| 15 |
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| 16 | #### Process sub from external process to stdin
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| 17 | seq 3 > >(tac)
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| 18 | ## STDOUT:
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| 19 | 3
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| 20 | 2
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| 21 | 1
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| 22 | ## END
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| 23 |
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| 24 | #### Process sub from shell to stdin
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| 25 | { echo 1; echo 2; echo 3; } > >(tac)
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| 26 | ## STDOUT:
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| 27 | 3
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| 28 | 2
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| 29 | 1
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| 30 | ## END
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| 31 |
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| 32 | #### Non-linear pipeline with >()
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| 33 | stdout_stderr() {
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| 34 | echo o1
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| 35 | echo o2
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| 36 |
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| 37 | sleep 0.1 # Does not change order
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| 38 |
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| 39 | { echo e1;
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| 40 | echo warning: e2
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| 41 | echo e3;
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| 42 | } >& 2
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| 43 | }
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| 44 | stdout_stderr 2> >(grep warning) | tac >$TMP/out.txt
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| 45 | wait $! # this does nothing in bash 4.3, but probably does in bash 4.4.
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| 46 | echo OUT
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| 47 | cat $TMP/out.txt
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| 48 | # PROBLEM -- OUT comes first, and then 'warning: e2', and then 'o2 o1'. It
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| 49 | # looks like it's because nobody waits for the proc sub.
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| 50 | # http://lists.gnu.org/archive/html/help-bash/2017-06/msg00018.html
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| 51 | ## STDOUT:
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| 52 | OUT
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| 53 | warning: e2
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| 54 | o2
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| 55 | o1
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| 56 | ## END
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| 57 |
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| 58 | #### $(<file) idiom with process sub
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| 59 | echo FOO >foo
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| 60 |
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| 61 | # works in bash and zsh
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| 62 | echo $(<foo)
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| 63 |
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| 64 | # this works in zsh, but not in bash
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| 65 | tr A-Z a-z < <(<foo)
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| 66 |
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| 67 | cat < <(<foo; echo hi)
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| 68 |
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| 69 | ## STDOUT:
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| 70 | FOO
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| 71 | hi
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| 72 | ## END
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| 73 | ## OK zsh STDOUT:
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| 74 | FOO
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| 75 | foo
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| 76 | FOO
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| 77 | hi
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| 78 | ## END
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| 79 |
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| 80 | #### status code is available
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| 81 |
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| 82 | shopt --set parse_at
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| 83 |
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| 84 | cat <(seq 2; exit 2) <(seq 3; exit 3)
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| 85 |
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| 86 | case $SH in bash*|zsh) exit ;; esac
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| 87 |
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| 88 | echo status @_process_sub_status
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| 89 | echo done
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| 90 |
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| 91 | ## STDOUT:
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| 92 | 1
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| 93 | 2
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| 94 | 1
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| 95 | 2
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| 96 | 3
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| 97 | status 2 3
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| 98 | done
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| 99 | ## END
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| 100 | ## N-I bash/zsh STDOUT:
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| 101 | 1
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| 102 | 2
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| 103 | 1
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| 104 | 2
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| 105 | 3
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| 106 | ## END
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| 107 |
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| 108 | #### shopt -s process_sub_fail
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| 109 |
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| 110 | case $SH in bash*|zsh) exit ;; esac
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| 111 |
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| 112 | shopt --set parse_at
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| 113 |
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| 114 | cat <(echo a; exit 2) <(echo b; exit 3)
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| 115 | echo status=$? ps @_process_sub_status
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| 116 |
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| 117 | echo __
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| 118 | shopt -s process_sub_fail
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| 119 |
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| 120 | cat <(echo a; exit 2) <(echo b; exit 3)
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| 121 | echo status=$? ps @_process_sub_status
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| 122 |
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| 123 | # Now exit because of it
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| 124 | set -o errexit
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| 125 |
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| 126 | cat <(echo a; exit 2) <(echo b; exit 3)
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| 127 | echo status=$? ps @_process_sub_status
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| 128 |
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| 129 | ## status: 3
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| 130 | ## STDOUT:
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| 131 | a
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| 132 | b
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| 133 | status=0 ps 2 3
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| 134 | __
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| 135 | a
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| 136 | b
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| 137 | status=3 ps 2 3
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| 138 | a
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| 139 | b
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| 140 | ## END
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| 141 | ## N-I bash/zsh status: 0
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| 142 | ## N-I bash/zsh STDOUT:
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| 143 | ## END
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| 144 |
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| 145 | #### process subs and pipelines together
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| 146 |
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| 147 | # zsh is very similar to bash, but don't bother with the assertions
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| 148 | case $SH in bash*|zsh) exit ;; esac
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| 149 |
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| 150 | shopt --set parse_at
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| 151 |
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| 152 | f() {
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| 153 | cat <(seq 1; exit 1) | {
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| 154 | cat <(seq 2; exit 2) <(seq 3; exit 3)
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| 155 |
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| 156 | # 2022-11 workaround for race condition: sometimes we get pipeline=141 4
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| 157 | # instead of pipeline=0 4, which means that the first 'cat' got SIGPIPE.
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| 158 | # If we make this part of the pipeline take longer, then 'cat' should have
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| 159 | # a chance to finish.
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| 160 |
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| 161 | sleep 0.01
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| 162 |
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| 163 | (exit 4)
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| 164 | }
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| 165 | echo status=$?
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| 166 | echo process_sub @_process_sub_status
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| 167 | echo pipeline @_pipeline_status
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| 168 | echo __
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| 169 | }
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| 170 |
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| 171 | f
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| 172 |
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| 173 | ## STDOUT:
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| 174 | 1
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| 175 | 2
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| 176 | 1
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| 177 | 2
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| 178 | 3
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| 179 | status=4
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| 180 | process_sub 2 3
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| 181 | pipeline 0 4
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| 182 | __
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| 183 | ## END
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| 184 | ## N-I bash/zsh STDOUT:
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| 185 | ## END
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| 186 |
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| 187 | #### process sub in background &
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| 188 |
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| 189 | cat <(seq 3; sleep 0.1) & wait
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| 190 |
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| 191 | echo sync
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| 192 |
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| 193 | # This one escapes, and the shell should still exit
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| 194 | cat <(sleep 0.1) &
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| 195 |
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| 196 | echo fork
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| 197 |
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| 198 | ## STDOUT:
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| 199 | 1
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| 200 | 2
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| 201 | 3
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| 202 | sync
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| 203 | fork
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| 204 | ## END
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