Category:TXR: Difference between revisions
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(Ported to Windows natively.) |
(→Simple Query: Extremely simple query.) |
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The success of a directive means that computation proceeds to the next directive (and, if this is a pattern match, the input position advances). Failure means that the enclosing query fails, triggering back-tracking behaviors and possibly failure of the entire query. |
The success of a directive means that computation proceeds to the next directive (and, if this is a pattern match, the input position advances). Failure means that the enclosing query fails, triggering back-tracking behaviors and possibly failure of the entire query. |
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==Extremely Simple Query== |
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Extract first matching line from the password file. Of course, TXR matches are not restricted to single line! |
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<lang bash>$ txr -c '@(skip) |
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@user:@pw:@uid:@gid:@gecos:@home:@shell' /etc/passwd</lang> |
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<pre> |
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user="root" |
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pw="x" |
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uid="0" |
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gid="0" |
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gecos="root" |
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home="/root" |
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shell="/bin/bash"</pre> |
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Now, pre-bind the <code>user</code> variable first to retrieve some other user. Now <code>@(skip)</code> kicks into action, skipping non-matching material: |
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<lang bash>$ txr -Duser=sshd -c '@(skip) |
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@user:@pw:@uid:@gid:@gecos:@home:@shell' /etc/passwd</lang> |
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<pre>user="sshd" |
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pw="x" |
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uid="114" |
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gid="65534" |
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gecos="" |
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home="/var/run/sshd" |
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shell="/usr/sbin/nologin"</pre> |
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==Simple Query== |
==Simple Query== |
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