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Diffstat (limited to 'doc/backtick.html')
| -rw-r--r-- | doc/backtick.html | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/doc/backtick.html b/doc/backtick.html index 14cc031..38c02a2 100644 --- a/doc/backtick.html +++ b/doc/backtick.html @@ -49,10 +49,15 @@ output as a value. </li> <li> <tt>-N</tt> : store <em>prog1...</em>'s output as is, including the last newline, if any. </li> <li> <tt>-n</tt> : chomp an ending newline off <em>prog1...</em>'s output. This is the default. </li> <li> <tt>-e</tt> : no autoimport. This is the default. </li> - <li> <tt>-E</tt> : autoimport. Instead of exec'ing into -<em>prog2...</em>, exec into <tt>importas -ui <em>variable</em> <em>variable</em> -<em>prog2...</em></tt>. This substitutes <em>variable</em> into the command -line instead of putting it into the environment. </li> + <li> <tt>-E</tt> : autoimport. Before exec'ing into +<em>prog2...</em>, perform a +<a href="https://skarnet.org/software/execline/el_substitute.html">substitution</a> +so that <tt>$?</tt> is replaced with <em>prog1...</em>'s exitcode (if +applicable, see below), and +<tt>${<em>variable</em>}</tt> is replaced with <em>prog1...</em>'s output, +instead of keeping the results in the environment. The variables will not +appear in the environment; if they preexisted in <tt>backtick</tt>'s +environment, they will be removed. </li> </ul> <p> @@ -76,5 +81,13 @@ the environment, and execution proceeds. </li> is set to <em>default</em>, and execution proceeds. </li> </ul> +<p> + If the command line can keep running after <em>prog1</em> crashes or exits +nonzero, i.e. if one of the <tt>-I</tt>, <tt>-x</tt> -or <tt>-D</tt> has been +given, then <tt>backtick</tt> also adds the <tt>?</tt> variable to the +environment; it then contains an <a href="exitcodes.html">approximation</a> +of <em>prog1</em>'s exit code. +</p> + </body> </html> |