1 |
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2 | ## compare_shells: bash dash mksh ash
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3 |
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4 | # OSH mechanisms:
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5 | #
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6 | # - shopt -s strict_errexit
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7 | # - shopt -s command_sub_errexit
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8 | # - inherit_errexit (bash)
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9 | #
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10 | # Summary:
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11 | # - local assignment is different than global! The exit code and errexit
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12 | # behavior are different because the concept of the "last command" is
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13 | # different.
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14 | # - ash has copied bash behavior!
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15 |
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16 | #### command sub: errexit is NOT inherited and outer shell keeps going
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17 |
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18 | # This is the bash-specific bug here:
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19 | # https://blogs.janestreet.com/when-bash-scripts-bite/
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20 | # See inherit_errexit below.
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21 | #
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22 | # I remember finding a script that relies on bash's bad behavior, so OSH copies
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23 | # it. But you can opt in to better behavior.
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24 |
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25 | set -o errexit
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26 | echo $(echo one; false; echo two) # bash/ash keep going
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27 | echo parent status=$?
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28 | ## STDOUT:
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29 | one two
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30 | parent status=0
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31 | ## END
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32 | # dash and mksh: inner shell aborts, but outer one keeps going!
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33 | ## OK dash/mksh STDOUT:
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34 | one
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35 | parent status=0
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36 | ## END
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37 |
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38 | #### command sub with inherit_errexit only
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39 | set -o errexit
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40 | shopt -s inherit_errexit || true
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41 | echo zero
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42 | echo $(echo one; false; echo two) # bash/ash keep going
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43 | echo parent status=$?
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44 | ## STDOUT:
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45 | zero
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46 | one
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47 | parent status=0
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48 | ## END
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49 | ## N-I ash STDOUT:
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50 | zero
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51 | one two
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52 | parent status=0
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53 | ## END
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54 |
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55 | #### strict_errexit and assignment builtins (local, export, readonly ...)
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56 | set -o errexit
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57 | shopt -s strict_errexit || true
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58 | #shopt -s command_sub_errexit || true
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59 |
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60 | f() {
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61 | local x=$(echo hi; false)
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62 | echo x=$x
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63 | }
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64 |
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65 | eval 'f'
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66 | echo ---
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67 |
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68 | ## status: 1
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69 | ## STDOUT:
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70 | ## END
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71 | ## N-I dash/bash/mksh/ash status: 0
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72 | ## N-I dash/bash/mksh/ash STDOUT:
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73 | x=hi
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74 | ---
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75 | ## END
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76 |
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77 | #### strict_errexit and command sub in export / readonly
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78 | case $SH in (dash|bash|mksh|ash) exit ;; esac
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79 |
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80 | $SH -o errexit -O strict_errexit -c 'echo a; export x=$(might-fail); echo b'
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81 | echo status=$?
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82 | $SH -o errexit -O strict_errexit -c 'echo a; readonly x=$(might-fail); echo b'
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83 | echo status=$?
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84 | $SH -o errexit -O strict_errexit -c 'echo a; x=$(true); echo b'
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85 | echo status=$?
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86 |
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87 | ## STDOUT:
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88 | a
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89 | status=1
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90 | a
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91 | status=1
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92 | a
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93 | b
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94 | status=0
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95 | ## END
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96 | ## N-I dash/bash/mksh/ash stdout-json: ""
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97 |
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98 |
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99 | #### strict_errexit disallows pipeline
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100 | set -o errexit
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101 | shopt -s strict_errexit || true
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102 |
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103 | if echo 1 | grep 1; then
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104 | echo one
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105 | fi
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106 |
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107 | ## status: 1
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108 | ## N-I dash/bash/mksh/ash status: 0
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109 | ## N-I dash/bash/mksh/ash STDOUT:
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110 | 1
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111 | one
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112 | ## END
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113 |
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114 | #### strict_errexit allows singleton pipeline
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115 | set -o errexit
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116 | shopt -s strict_errexit || true
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117 |
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118 | if ! false; then
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119 | echo yes
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120 | fi
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121 |
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122 | ## STDOUT:
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123 | yes
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124 | ## END
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125 |
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126 | #### strict_errexit without errexit proc
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127 | myproc() {
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128 | echo myproc
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129 | }
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130 | myproc || true
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131 |
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132 | # This should be a no-op I guess
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133 | shopt -s strict_errexit || true
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134 | myproc || true
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135 |
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136 | ## status: 1
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137 | ## STDOUT:
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138 | myproc
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139 | ## END
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140 | ## N-I dash/bash/mksh/ash status: 0
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141 | ## N-I dash/bash/mksh/ash STDOUT:
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142 | myproc
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143 | myproc
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144 | ## END
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145 |
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146 | #### strict_errexit without errexit proc / command sub
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147 |
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148 | # Implementation quirk:
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149 | # - The proc check happens only if errexit WAS on and is disabled
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150 | # - But 'shopt --unset allow_csub_psub' happens if it was never on
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151 |
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152 | shopt -s strict_errexit || true
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153 |
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154 | p() {
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155 | echo before
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156 | local x
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157 | # This line fails, which is a bit weird, but errexit
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158 | x=$(false)
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159 | echo x=$x
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160 | }
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161 |
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162 | if p; then
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163 | echo ok
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164 | fi
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165 |
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166 | ## N-I dash/bash/mksh/ash status: 0
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167 | ## N-I dash/bash/mksh/ash STDOUT:
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168 | before
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169 | x=
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170 | ok
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171 | ## END
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172 | ## status: 1
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173 | ## STDOUT:
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174 | ## END
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175 |
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176 | #### strict_errexit and errexit disabled
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177 | case $SH in (dash|bash|mksh|ash) exit ;; esac
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178 |
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179 | shopt -s parse_brace strict_errexit || true
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180 |
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181 | p() {
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182 | echo before
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183 | local x
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184 | # This line fails, which is a bit weird, but errexit
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185 | x=$(false)
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186 | echo x=$x
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187 | }
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188 |
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189 | set -o errexit
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190 | shopt --unset errexit {
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191 | # It runs normally here, because errexit was disabled (just not by a
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192 | # conditional)
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193 | p
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194 | }
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195 | ## N-I dash/bash/mksh/ash STDOUT:
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196 | ## END
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197 | ## STDOUT:
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198 | before
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199 | x=
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200 | ## END
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201 |
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202 |
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203 | #### command sub with command_sub_errexit only
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204 | set -o errexit
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205 | shopt -s command_sub_errexit || true
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206 | echo zero
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207 | echo $(echo one; false; echo two) # bash/ash keep going
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208 | echo parent status=$?
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209 | ## STDOUT:
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210 | zero
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211 | one two
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212 | parent status=0
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213 | ## END
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214 | ## N-I dash/mksh STDOUT:
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215 | zero
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216 | one
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217 | parent status=0
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218 | ## END
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219 |
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220 | #### command_sub_errexit stops at first error
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221 | case $SH in (dash|bash|mksh|ash) exit ;; esac
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222 |
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223 | set -o errexit
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224 | shopt --set parse_brace command_sub_errexit verbose_errexit || true
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225 |
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226 | rm -f BAD
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227 |
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228 | try {
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229 | echo $(date %d) $(touch BAD)
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230 | }
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231 | if ! test -f BAD; then # should not exist
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232 | echo OK
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233 | fi
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234 |
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235 | ## STDOUT:
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236 | OK
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237 | ## END
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238 | ## N-I dash/bash/mksh/ash STDOUT:
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239 | ## END
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240 |
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241 | #### command sub with inherit_errexit and command_sub_errexit
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242 | set -o errexit
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243 |
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244 | # bash implements inherit_errexit, but it's not as strict as OSH.
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245 | shopt -s inherit_errexit || true
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246 | shopt -s command_sub_errexit || true
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247 | echo zero
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248 | echo $(echo one; false; echo two) # bash/ash keep going
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249 | echo parent status=$?
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250 | ## STDOUT:
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251 | zero
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252 | ## END
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253 | ## status: 1
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254 | ## N-I dash/mksh/bash status: 0
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255 | ## N-I dash/mksh/bash STDOUT:
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256 | zero
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257 | one
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258 | parent status=0
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259 | ## END
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260 | ## N-I ash status: 0
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261 | ## N-I ash STDOUT:
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262 | zero
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263 | one two
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264 | parent status=0
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265 | ## END
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266 |
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267 | #### command sub: last command fails but keeps going and exit code is 0
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268 | set -o errexit
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269 | echo $(echo one; false) # we lost the exit code
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270 | echo status=$?
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271 | ## STDOUT:
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272 | one
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273 | status=0
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274 | ## END
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275 |
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276 | #### global assignment with command sub: middle command fails
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277 | set -o errexit
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278 | s=$(echo one; false; echo two;)
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279 | echo "$s"
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280 | ## status: 0
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281 | ## STDOUT:
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282 | one
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283 | two
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284 | ## END
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285 | # dash and mksh: whole thing aborts!
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286 | ## OK dash/mksh stdout-json: ""
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287 | ## OK dash/mksh status: 1
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288 |
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289 | #### global assignment with command sub: last command fails and it aborts
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290 | set -o errexit
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291 | s=$(echo one; false)
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292 | echo status=$?
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293 | ## stdout-json: ""
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294 | ## status: 1
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295 |
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296 | #### local: middle command fails and keeps going
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297 | set -o errexit
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298 | f() {
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299 | echo good
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300 | local x=$(echo one; false; echo two)
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301 | echo status=$?
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302 | echo $x
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303 | }
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304 | f
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305 | ## STDOUT:
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306 | good
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307 | status=0
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308 | one two
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309 | ## END
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310 | # for dash and mksh, the INNER shell aborts, but the outer one keeps going!
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311 | ## OK dash/mksh STDOUT:
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312 | good
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313 | status=0
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314 | one
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315 | ## END
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316 |
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317 | #### local: last command fails and also keeps going
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318 | set -o errexit
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319 | f() {
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320 | echo good
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321 | local x=$(echo one; false)
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322 | echo status=$?
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323 | echo $x
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324 | }
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325 | f
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326 | ## STDOUT:
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327 | good
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328 | status=0
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329 | one
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330 | ## END
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331 |
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332 | #### local and inherit_errexit / command_sub_errexit
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333 | # I've run into this problem a lot.
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334 | set -o errexit
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335 | shopt -s inherit_errexit || true # bash option
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336 | shopt -s command_sub_errexit || true # oil option
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337 | f() {
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338 | echo good
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339 | local x=$(echo one; false; echo two)
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340 | echo status=$?
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341 | echo $x
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342 | }
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343 | f
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344 | ## status: 1
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345 | ## STDOUT:
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346 | good
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347 | ## END
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348 | ## N-I ash status: 0
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349 | ## N-I ash STDOUT:
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350 | good
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351 | status=0
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352 | one two
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353 | ## END
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354 | ## N-I bash/dash/mksh status: 0
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355 | ## N-I bash/dash/mksh STDOUT:
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356 | good
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357 | status=0
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358 | one
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359 | ## END
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360 |
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361 | #### global assignment when last status is failure
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362 | # this is a bug I introduced
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363 | set -o errexit
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364 | x=$(false) || true # from abuild
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365 | [ -n "$APORTSDIR" ] && true
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366 | BUILDDIR=${_BUILDDIR-$BUILDDIR}
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367 | echo status=$?
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368 | ## STDOUT:
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369 | status=0
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370 | ## END
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371 |
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372 | #### strict_errexit prevents errexit from being disabled in function
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373 | set -o errexit
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374 | fun() { echo fun; }
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375 |
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376 | fun || true # this is OK
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377 |
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378 | shopt -s strict_errexit || true
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379 |
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380 | echo 'builtin ok' || true
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381 | env echo 'external ok' || true
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382 |
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383 | fun || true # this fails
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384 |
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385 | ## status: 1
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386 | ## STDOUT:
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387 | fun
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388 | builtin ok
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389 | external ok
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390 | ## END
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391 | ## N-I dash/bash/mksh/ash status: 0
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392 | ## N-I dash/bash/mksh/ash STDOUT:
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393 | fun
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394 | builtin ok
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395 | external ok
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396 | fun
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397 | ## END
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398 |
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399 | #### strict_errexit prevents errexit from being disabled in brace group
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400 | set -o errexit
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401 | # false failure is NOT respected either way
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402 | { echo foo; false; echo bar; } || echo "failed"
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403 |
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404 | shopt -s strict_errexit || true
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405 | { echo foo; false; echo bar; } || echo "failed"
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406 | ## status: 1
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407 | ## STDOUT:
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408 | foo
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409 | bar
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410 | ## END
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411 |
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412 | ## N-I dash/bash/mksh/ash status: 0
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413 | ## N-I dash/bash/mksh/ash STDOUT:
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414 | foo
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415 | bar
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416 | foo
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417 | bar
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418 | ## END
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419 |
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420 | #### strict_errexit prevents errexit from being disabled in subshell
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421 | set -o errexit
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422 | shopt -s inherit_errexit || true
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423 |
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424 | # false failure is NOT respected either way
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425 | ( echo foo; false; echo bar; ) || echo "failed"
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426 |
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427 | shopt -s strict_errexit || true
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428 | ( echo foo; false; echo bar; ) || echo "failed"
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429 | ## status: 1
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430 | ## STDOUT:
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431 | foo
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432 | bar
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433 | ## END
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434 |
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435 | ## N-I dash/bash/mksh/ash status: 0
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436 | ## N-I dash/bash/mksh/ash STDOUT:
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437 | foo
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438 | bar
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439 | foo
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440 | bar
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441 | ## END
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442 |
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443 | #### strict_errexit and ! && || if while until
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444 | prelude='set -o errexit
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445 | shopt -s strict_errexit || true
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446 | fun() { echo fun; }'
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447 |
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448 | $SH -c "$prelude; ! fun; echo 'should not get here'"
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449 | echo bang=$?
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450 | echo --
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451 |
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452 | $SH -c "$prelude; fun || true"
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453 | echo or=$?
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454 | echo --
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455 |
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456 | $SH -c "$prelude; fun && true"
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457 | echo and=$?
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458 | echo --
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459 |
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460 | $SH -c "$prelude; if fun; then true; fi"
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461 | echo if=$?
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462 | echo --
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463 |
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464 | $SH -c "$prelude; while fun; do echo while; exit; done"
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465 | echo while=$?
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466 | echo --
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467 |
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468 | $SH -c "$prelude; until fun; do echo until; exit; done"
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469 | echo until=$?
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470 | echo --
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471 |
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472 |
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473 | ## STDOUT:
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474 | bang=1
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475 | --
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476 | or=1
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477 | --
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478 | and=1
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479 | --
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480 | if=1
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481 | --
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482 | while=1
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483 | --
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484 | until=1
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485 | --
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486 | ## END
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487 | ## N-I dash/bash/mksh/ash STDOUT:
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488 | fun
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489 | should not get here
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490 | bang=0
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491 | --
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492 | fun
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493 | or=0
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494 | --
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495 | fun
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496 | and=0
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497 | --
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498 | fun
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499 | if=0
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500 | --
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501 | fun
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502 | while
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503 | while=0
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504 | --
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505 | fun
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506 | until=0
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507 | --
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508 | ## END
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509 |
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510 | #### if pipeline doesn't fail fatally
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511 | set -o errexit
|
512 | set -o pipefail
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513 |
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514 | f() {
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515 | local dir=$1
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516 | if ls $dir | grep ''; then
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517 | echo foo
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518 | echo ${PIPESTATUS[@]}
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519 | fi
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520 | }
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521 | rmdir $TMP/_tmp || true
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522 | rm -f $TMP/*
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523 | f $TMP
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524 | f /nonexistent # should fail
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525 | echo done
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526 |
|
527 | ## N-I dash status: 2
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528 | ## N-I dash stdout-json: ""
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529 | ## STDOUT:
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530 | done
|
531 | ## END
|
532 |
|
533 | #### errexit is silent (verbose_errexit for Oil)
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534 | shopt -u verbose_errexit 2>/dev/null || true
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535 | set -e
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536 | false
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537 | ## stderr-json: ""
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538 | ## status: 1
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539 |
|
540 | #### command sub errexit preserves exit code
|
541 | set -e
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542 | shopt -s command_sub_errexit || true
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543 |
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544 | echo before
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545 | echo $(exit 42)
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546 | echo after
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547 | ## STDOUT:
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548 | before
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549 | ## END
|
550 | ## status: 42
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551 | ## N-I dash/bash/mksh/ash STDOUT:
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552 | before
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553 |
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554 | after
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555 | ## N-I dash/bash/mksh/ash status: 0
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556 |
|
557 | #### What's in strict:all?
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558 |
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559 | # inherit_errexit, strict_errexit, but not command_sub_errexit!
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560 | # for that you need oil:upgrade!
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561 |
|
562 | set -o errexit
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563 | shopt -s strict:all || true
|
564 |
|
565 | # inherit_errexit is bash compatible, so we have it
|
566 | #echo $(date %x)
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567 |
|
568 | # command_sub_errexit would hide errors!
|
569 | f() {
|
570 | local d=$(date %x)
|
571 | }
|
572 | f
|
573 |
|
574 | deploy_func() {
|
575 | echo one
|
576 | false
|
577 | echo two
|
578 | }
|
579 |
|
580 | if ! deploy_func; then
|
581 | echo failed
|
582 | fi
|
583 |
|
584 | echo 'should not get here'
|
585 |
|
586 | ## status: 1
|
587 | ## STDOUT:
|
588 | ## END
|
589 | ## N-I dash/bash/mksh/ash status: 0
|
590 | ## N-I dash/bash/mksh/ash STDOUT:
|
591 | one
|
592 | two
|
593 | should not get here
|
594 | ## END
|
595 |
|
596 | #### command_sub_errexit causes local d=$(date %x) to fail
|
597 | set -o errexit
|
598 | shopt -s inherit_errexit || true
|
599 | #shopt -s strict_errexit || true
|
600 | shopt -s command_sub_errexit || true
|
601 |
|
602 | myproc() {
|
603 | # this is disallowed because we want a runtime error 100% of the time
|
604 | local x=$(true)
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605 |
|
606 | # Realistic example. Should fail here but shells don't!
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607 | local d=$(date %x)
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608 | echo hi
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609 | }
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610 | myproc
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611 |
|
612 | ## status: 1
|
613 | ## STDOUT:
|
614 | ## END
|
615 | ## N-I dash/bash/mksh/ash status: 0
|
616 | ## N-I dash/bash/mksh/ash STDOUT:
|
617 | hi
|
618 | ## END
|
619 |
|
620 | #### command_sub_errexit and command sub in array
|
621 | case $SH in (dash|ash|mksh) exit ;; esac
|
622 |
|
623 | set -o errexit
|
624 | shopt -s inherit_errexit || true
|
625 | #shopt -s strict_errexit || true
|
626 | shopt -s command_sub_errexit || true
|
627 |
|
628 | # We don't want silent failure here
|
629 | readonly -a myarray=( one "$(date %x)" two )
|
630 |
|
631 | #echo len=${#myarray[@]}
|
632 | argv.py "${myarray[@]}"
|
633 | ## status: 1
|
634 | ## STDOUT:
|
635 | ## END
|
636 | ## N-I bash status: 0
|
637 | ## N-I bash STDOUT:
|
638 | ['one', '', 'two']
|
639 | ## END
|
640 | ## N-I dash/ash/mksh status: 0
|
641 |
|
642 | #### OLD: command sub in conditional, with inherit_errexit
|
643 | set -o errexit
|
644 | shopt -s inherit_errexit || true
|
645 | if echo $(echo 1; false; echo 2); then
|
646 | echo A
|
647 | fi
|
648 | echo done
|
649 |
|
650 | ## STDOUT:
|
651 | 1 2
|
652 | A
|
653 | done
|
654 | ## END
|
655 | ## N-I dash/mksh STDOUT:
|
656 | 1
|
657 | A
|
658 | done
|
659 | ## END
|
660 |
|
661 | #### OLD: command sub in redirect in conditional
|
662 | set -o errexit
|
663 |
|
664 | if echo tmp_contents > $(echo tmp); then
|
665 | echo 2
|
666 | fi
|
667 | cat tmp
|
668 | ## STDOUT:
|
669 | 2
|
670 | tmp_contents
|
671 | ## END
|
672 |
|
673 | #### Regression
|
674 | case $SH in (bash|dash|ash|mksh) exit ;; esac
|
675 |
|
676 | shopt --set oil:upgrade
|
677 |
|
678 | shopt --unset errexit {
|
679 | echo hi
|
680 | }
|
681 |
|
682 | proc p {
|
683 | echo p
|
684 | }
|
685 |
|
686 | shopt --unset errexit {
|
687 | p
|
688 | }
|
689 | ## STDOUT:
|
690 | hi
|
691 | p
|
692 | ## END
|
693 | ## N-I bash/dash/ash/mksh stdout-json: ""
|
694 |
|
695 | #### ShAssignment used as conditional
|
696 |
|
697 | while x=$(false)
|
698 | do
|
699 | echo while
|
700 | done
|
701 |
|
702 | if x=$(false)
|
703 | then
|
704 | echo if
|
705 | fi
|
706 |
|
707 | if x=$(true)
|
708 | then
|
709 | echo yes
|
710 | fi
|
711 |
|
712 | # Same thing with errexit -- NOT affected
|
713 | set -o errexit
|
714 |
|
715 | while x=$(false)
|
716 | do
|
717 | echo while
|
718 | done
|
719 |
|
720 | if x=$(false)
|
721 | then
|
722 | echo if
|
723 | fi
|
724 |
|
725 | if x=$(true)
|
726 | then
|
727 | echo yes
|
728 | fi
|
729 |
|
730 | # Same thing with strict_errexit -- NOT affected
|
731 | shopt -s strict_errexit || true
|
732 |
|
733 | while x=$(false)
|
734 | do
|
735 | echo while
|
736 | done
|
737 |
|
738 | if x=$(false)
|
739 | then
|
740 | echo if
|
741 | fi
|
742 |
|
743 | if x=$(true)
|
744 | then
|
745 | echo yes
|
746 | fi
|
747 |
|
748 | ## status: 1
|
749 | ## STDOUT:
|
750 | yes
|
751 | yes
|
752 | ## END
|
753 | ## N-I dash/bash/mksh/ash status: 0
|
754 | ## N-I dash/bash/mksh/ash STDOUT:
|
755 | yes
|
756 | yes
|
757 | yes
|
758 | ## END
|