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Full Discussion: Am I abusing backticks?
Top Forums Shell Programming and Scripting Am I abusing backticks? Post 302323158 by mglenney on Friday 5th of June 2009 02:44:56 PM
Old 06-05-2009
Am I abusing backticks?

I'm always concerned I might be abusing backticks within my scripts. A current script I'm writing has this for example:

stripscriptname=`echo $scriptname | sed 's/\(.*\)\..*/\1/'`
stripsearch=`echo $searchpattern | tr -d ' ,/'`

Both of these variables are set inside the script (in fact, $scriptname is set with "scriptname=`basename $0`") so it seems to me that I shouldn't need to use backticks but I don't know a better way to do this.

Am I abusing backticks? Is there a better way to accomplish what I did in the above examples?

MG
 

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DH_INSTALLINIT(1)						     Debhelper							 DH_INSTALLINIT(1)

NAME
dh_installinit - install service init files into package build directories SYNOPSIS
dh_installinit [debhelperoptions] [--name=name] [-n] [-R] [-r] [-d] [--params] DESCRIPTION
dh_installinit is a debhelper program that is responsible for installing init scripts with associated defaults files. In compatibility levels up to 11, dh_installinit also handled upstart job files and systemd service files. It also automatically generates the postinst and postrm and prerm commands needed to set up the symlinks in /etc/rc*.d/ to start and stop the init scripts. In compat 10 or earlier: If a package only ships a systemd service file and no sysvinit script is provided, you may want to exclude the call to dh_installinit for that package (e.g. via -N). Otherwise, you may get warnings from lintian about init.d scripts not being included in the package. FILES
debian/package.init If this exists, it is installed into etc/init.d/package in the package build directory. debian/package.default If this exists, it is installed into etc/default/package in the package build directory. debian/package.upstart In compatibility level 11, this file will trigger an error with a reminder about ensuring the proper removal of the upstart file in the previous package version. Please consider using the "rm_conffile" feature from dh_installdeb(1) to ensure the proper removal of previous upstart files. In compatibility level 10, if this file exists, it is installed into etc/init/package.conf in the package build directory. debian/package.service If this exists, it is installed into lib/systemd/system/package.service in the package build directory. Only used in compat levels 10 and below. debian/package.tmpfile If this exists, it is installed into usr/lib/tmpfiles.d/package.conf in the package build directory. (The tmpfiles.d mechanism is currently only used by systemd.) Only used in compat levels 10 and below. OPTIONS
-n, --no-scripts Do not modify postinst/postrm/prerm scripts. -o, --only-scripts Only modify postinst/postrm/prerm scripts, do not actually install any init script, default files, upstart job or systemd service file. May be useful if the file is shipped and/or installed by upstream in a way that doesn't make it easy to let dh_installinit find it. Caveat: This will bypass all the regular checks and unconditionally modify the scripts. You will almost certainly want to use this with -p to limit, which packages are affected by the call. Example: override_dh_installinit: dh_installinit -pfoo --only-scripts dh_installinit --remaining -R, --restart-after-upgrade Do not stop the init script until after the package upgrade has been completed. This is the default behaviour in compat 10. In early compat levels, the default was to stop the script in the prerm, and starts it again in the postinst. This can be useful for daemons that should not have a possibly long downtime during upgrade. But you should make sure that the daemon will not get confused by the package being upgraded while it's running before using this option. --no-restart-after-upgrade Undo a previous --restart-after-upgrade (or the default of compat 10). If no other options are given, this will cause the service to be stopped in the prerm script and started again in the postinst script. -r, --no-stop-on-upgrade, --no-restart-on-upgrade Do not stop init script on upgrade. This has the side-effect of not restarting the service as a part of the upgrade. If you want to restart the service with minimal downtime, please use --restart-after-upgrade (default in compat 10 or later). If you want the service to be restarted but be stopped during the upgrade, then please use --no-restart-after-upgrade (note the "after- upgrade"). Note that the --no-restart-on-upgrade alias is deprecated and will be removed in compat 12. This is to avoid confusion with the --no-restart-after-upgrade option. The --no-stop-on-upgrade variant was introduced in debhelper 10.2 (included in Debian stretch). --no-start Do not start the init script on install or upgrade, or stop it on removal. Only call update-rc.d. Useful for rcS scripts. --no-enable Disable the init script on purge, but do not enable them on install. This implies a versioned dependency on init-system-helpers (= 1.51)> as it is the first (functional) version that supports <update-rc.d <script defaults-disabled>>. Note that this option does not affect whether the services are started. Please remember to also use --no-start if the service should not be started. Cannot be combined with -uparams, --update-rcd-params=params, or -- params. -d, --remove-d Remove trailing d from the name of the package, and use the result for the filename the upstart job file is installed as in etc/init/ , and for the filename the init script is installed as in etc/init.d and the default file is installed as in etc/default/. This may be useful for daemons with names ending in d. (Note: this takes precedence over the --init-script parameter described below.) -uparams --update-rcd-params=params -- params Pass params to update-rc.d(8). If not specified, defaults (or defaults-disabled with --no-enable) will be passed to update-rc.d(8). Cannot be combined with --no-enable. --name=name Install the init script (and default file) as well as upstart job file using the filename name instead of the default filename, which is the package name. When this parameter is used, dh_installinit looks for and installs files named debian/package.name.init, debian/package.name.default and debian/package.name.upstart instead of the usual debian/package.init, debian/package.default and debian/package.upstart. --init-script=scriptname Use scriptname as the filename the init script is installed as in etc/init.d/ (and also use it as the filename for the defaults file, if it is installed). If you use this parameter, dh_installinit will look to see if a file in the debian/ directory exists that looks like package.scriptname and if so will install it as the init script in preference to the files it normally installs. This parameter is deprecated, use the --name parameter instead. This parameter is incompatible with the use of upstart jobs. --error-handler=function Call the named shell function if running the init script fails. The function should be provided in the prerm and postinst scripts, before the #DEBHELPER# token. NOTES
Note that this command is not idempotent. dh_prep(1) should be called between invocations of this command. Otherwise, it may cause multiple instances of the same text to be added to maintainer scripts. SEE ALSO
debhelper(7) This program is a part of debhelper. AUTHORS
Joey Hess <joeyh@debian.org> Steve Langasek <steve.langasek@canonical.com> Michael Stapelberg <stapelberg@debian.org> 11.1.6ubuntu2 2018-05-10 DH_INSTALLINIT(1)
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