| 1 | #!/usr/bin/env bash
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| 2 | #
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| 3 | # Compare the output of "jobs" in different shells
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| 4 | #
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| 5 | # Usage:
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| 6 | # $SH demo/jobs-builtin.sh <function name>
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| 7 |
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| 8 | set -o nounset
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| 9 | #set -o pipefail
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| 10 | set -o errexit
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| 11 |
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| 12 | # Notes:
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| 13 | # - the formats are consistent, because it's specified by POSIX
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| 14 | # - they use [1] [2] [3]
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| 15 | # - + is the default job for 'fg' and 'bg', which is also %%
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| 16 | # - - is the job that would become the default, which is also %-
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| 17 | #
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| 18 | # "[%d] %c %s %s\n", <job-number>, <current>, <state>, <command>
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| 19 | #
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| 20 | # https://pubs.opengroup.org/onlinepubs/9699919799/utilities/jobs.html
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| 21 | #
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| 22 | # TODO: YSH should print this as J8! So you can parse it.
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| 23 | #
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| 24 | # - dash is the only shell that doesn't show source code; it just shows | for pipe
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| 25 | # - mksh has some weird quoting, like \sleep 1
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| 26 | # - mksh and zsh doesn't show trailing &, but bash does
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| 27 | #
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| 28 |
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| 29 | show_jobs() {
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| 30 | echo ___
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| 31 |
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| 32 | # all shells support this long format which shows components of a pipeline
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| 33 | #if true; then
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| 34 | if true; then
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| 35 | jobs -l
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| 36 | else
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| 37 | jobs
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| 38 | fi
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| 39 | }
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| 40 |
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| 41 | myfunc() {
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| 42 | sleep 0.3
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| 43 | show_jobs
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| 44 |
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| 45 | sleep 0.4
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| 46 | show_jobs
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| 47 | }
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| 48 |
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| 49 |
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| 50 | demo() {
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| 51 | sleep 1 & sleep 2 &
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| 52 | show_jobs
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| 53 |
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| 54 | # In jobs -l, bash, zsh, and mksh all combine this onto one line:
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| 55 | # { echo pipe1; sleep 0.5; }
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| 56 |
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| 57 | { echo pipe1
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| 58 | sleep 0.5
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| 59 | } | tac | wc -l &
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| 60 |
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| 61 | show_jobs
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| 62 |
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| 63 | myfunc &
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| 64 |
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| 65 | # only bash supports wait -n
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| 66 | if test -n "${BASH_VERSION:-}"; then
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| 67 | wait -n
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| 68 | show_jobs
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| 69 | fi
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| 70 |
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| 71 | wait
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| 72 | show_jobs
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| 73 |
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| 74 | ls | wc -l
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| 75 | show_jobs
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| 76 | }
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| 77 |
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| 78 | many_jobs() {
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| 79 | sleep 0.90 &
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| 80 | sleep 0.91 &
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| 81 | sleep 0.92 &
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| 82 | sleep 0.93 &
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| 83 | sleep 0.94 &
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| 84 | sleep 0.95 &
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| 85 | sleep 0.96 &
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| 86 | sleep 0.97 &
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| 87 | sleep 0.98 &
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| 88 | sleep 0.99 &
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| 89 |
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| 90 | show_jobs
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| 91 |
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| 92 | # Testing this syntax
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| 93 | # Doesn't work because shells say "job %10 not created under job control"
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| 94 | # fg %10
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| 95 |
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| 96 | wait
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| 97 | show_jobs
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| 98 | }
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| 99 |
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| 100 | osh-debug() {
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| 101 | # lastpipe with 'read'
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| 102 | { echo x; sleep 0.1; } | sort | read x
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| 103 | jobs --debug
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| 104 |
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| 105 | # no lastpipe
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| 106 | { echo x; sleep 0.1; } | sort | wc -l
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| 107 | jobs --debug
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| 108 | }
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| 109 |
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| 110 | "$@"
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