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Full Discussion: Dangerous rm -rf command
The Lounge War Stories Dangerous rm -rf command Post 302948321 by Don Cragun on Sunday 28th of June 2015 08:58:08 PM
Old 06-28-2015
Quote:
Originally Posted by Riker1204
Code:
var="/some/place"
rm -rf "${vra}/"*

Does the rm command throw an error when ${vra} does not exist or does it simply proceed with a null byte or something followed by /* erasing everything in its path.

As a beginner in Linux / Bash everything seems to bring up a question.
This has been answered many times before. If the variable vra has not been defined, the command:
Code:
rm -rf "${vra}/"*

will invoke rm with one operand for every file in your system's root directory that does not start with a period. The rm command will then attempt to remove every file in the file hierarchies rooted in those pathnames and print a diagnostic message for every file it is unable to remove until you kill that command or wipe out your system.

UNIX and Linux system utilities are generally very happy to try to do whatever you tell them to even if you have told them to do something that could be disastrous. They don't generally try to second guess you and tell you you might be making a mistake.
 

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Canto(1)							       Canto								  Canto(1)

NAME
Canto - An ncurses RSS reader DESCRIPTION
Canto is an RSS reader built to be flexible and highly customizable on top of python. GETTING STARTED
Canto is the client, separate from the fetcher Canto-fetch. In order to update you must invoke canto-fetch on a regular basis. Usually the way to do that is to add a line into your crontab like this: * * * * * canto-fetch If you're not a fan of cron, then you can add `canto-fetch -b` to your startup scripts to have canto-fetch run as a daemon on its own. After you have your configuration file generated, just run `canto` and it will update for you, if canto-fetch hasn't been run already. COMMAND LINE USAGE
-h/--help Simple help -v/--version Print version -u/--update Update feeds before launching client. -l/--list List all configured feeds -a/--checkall Print number of new items. -n/--checknew [feed] Print number of new items in feed. -o/--opml Print feeds to stdout as OPML file. -i/--import [path] Import feeds from OPML file to your configuration. -r/--url [URL] Add feed at URL to your configuration. -t/--tag [tag] Set tag for feed added with -r -D/--dir [path] Set the configuration directory (default: ~/.canto/) -C/--conf [path] Set the configuration file (default: ~/.canto/conf) -L/--log [path] Set the log file (default: ~/.canto/log) -F/--fdir [path] Set the feed directory (default: ~/.canto/feeds) -S /--sdir [PATH] Set the path to execurl scripts (default ~/.canto/scripts/) INTERNAL USAGE
Within the program you can use the following (default) keys. These can be changed in your configuration file by using the "key" configura- tion option. UP / DOWN or k / j Select previous or next item. (next_item) (prev_item) PGUP / PGDOWN or o / l Goto previous or next tag. (next_tag) (prev_tag) RIGHT / LEFT Set item unread or read (just_unread) (just_read) [ / ] Cycle through defined filters (prev_filter) (next_filter) { / } Cycle through defined tag filters (prev_feed_filter) (next_feed_filter) - / = Cycle through defined tag sorts (prev_tag_sort) (next_tag_sort) < / > Cycle through defined tag sets (prev_tagset) (next_tagset) : Goto a specific tag (order of the config) (goto_tag) ; Goto a specific visible tag (goto_reltag) TAB Switch focus between list and reader (only useful with dedicated reader space) (switch) h Display this man page. (help) Space Read a story (reader) g Use the defined browser to goto the item's URL (goto) C / V Collapse/Uncollapse all tags (set_collapse_all) (unset_collapse_all) c Collapse/Uncollapse current tag (toggle_collapse_tag) f Inline search (inline_search) m Toggle item marked/unmark (toggle_mark) M Unmark all items (all_unmarked) n / p Goto next/previous marked item (next_mark) (prev_mark) , / . Goto next/previous unread item (next_unread) (prev_unread) r / u Mark tag read/unread (tag_read) (tag_unread) R / U Mark all read/unread (all_read) (all_unread) Ctrl+R Refresh feeds (force_update) Ctrl+L Redraw screen (refresh) Restart Canto (restart) q Quit Canto (quit) READER USAGE
Inside the reader, there are a number of different keys. These can be changed with the "reader_key" configuration option. UP / DOWN or k / j Scroll up/down if content off screen (scroll_up) (scroll_down) n / p goto next/previous item without closing reader l Enumerate links (toggle_show_links) g Choose a link to goto (goto) CONFIGURATION
The ~/.canto/conf.py file is where all of the configuration is. You can start by reading http://codezen.org/canto/config . If you're updat- ing from <= 0.6.x then you should read http://codezen.org/canto/config/#upgrading-from-06x . FILES
~/.canto/conf.py Main configuration file. ~/.canto/conf (without the extension) is also checked for compatibility. ~/.canto/log Everyday log file. ~/.canto/fetchlog Canto-fetch log file. ~/.canto/feeds/ This is the directory where the stories are recorded. BUGS
I'm sure there are some. If you run into a bug (a crash or bad behavior), then send please report it. Any of the methods described in http://codezen.org/canto/contact are acceptable. Also, please include your configuration and log files with the report. HOMEPAGE
http://codezen.org/canto AUTHOR
Jack Miller <jack@codezen.org> Version 0.7.10 27 July 2010 Canto(1)
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