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Full Discussion: Need some help with a bash script
Homework and Emergencies Homework & Coursework Questions Need some help with a bash script Post 302990948 by Eggsy on Friday 3rd of February 2017 09:10:25 AM
Old 02-03-2017
Thanks for your answer. Would you mind helping me to understand how exactly those statements work then.

Is my assumption that "grep s>/dev/null" and "grep r>/dev/null" check whether or not a filename contains an S and an R correct?

So looking over it again, for 2. would this mean it's invoked 15 times too, because it checks every single file.
And as for 3. could it be 7 times, since you only reach the "grep r>/dev/null" part when it found an S in the name (since there are only 7 files with an S)?

---------- Post updated at 09:10 AM ---------- Previous update was at 09:02 AM ----------

Quote:
Originally Posted by RudiC
Welcome to the forum.

As to your questions:

May I question your reasoning?
a) Where in the script are S or R to be matched? Both upper case?
b) Do you know the meaning of the || operator in shell scripts?

1. How many input items do you have? And, how is the end-of-file detected?
2. Once in the loop, how many times do you think the commands or lists will be executed?
3.and
4. Again: Do you know the meaning of || in shell scripts? How would it influence the execution of the command list?
5. Correct!
a) I believe the filenames were actually all lower case. (As a german, we capitalize names, so that was my mistake when I wrote this down)

b) || means we only reach the right side, when the left side is true, iirc. So once it found a filename with an "s", it checks for an "r"?

1. We have 15 items. So it goes through the list of files until every single one was checked?
2. Also 15 times, since it checks every single item for an "s"?
3. 7 times, since we only reach the second part, when we found an item with an "s"
4. 3 times, since we only reach that part, when we found an item with an "s" and an "r"
 

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LEARN ABOUT DEBIAN

dh_compress

DH_COMPRESS(1)							     Debhelper							    DH_COMPRESS(1)

NAME

       dh_compress - compress files and fix symlinks in package build directories

SYNOPSIS

       dh_compress [debhelperoptions] [-Xitem] [-A] [file...]

DESCRIPTION

       dh_compress is a debhelper program that is responsible for compressing the files in package build directories, and makes sure that any
       symlinks that pointed to the files before they were compressed are updated to point to the new files.

       By default, dh_compress compresses files that Debian policy mandates should be compressed, namely all files in usr/share/info,
       usr/share/man, files in usr/share/doc that are larger than 4k in size, (except the copyright file, .html and other web files, image files,
       and files that appear to be already compressed based on their extensions), and all changelog files. Plus PCF fonts underneath
       usr/share/fonts/X11/

FILES

       debian/package.compress
	   These files are deprecated.

	   If this file exists, the default files are not compressed. Instead, the file is ran as a shell script, and all filenames that the shell
	   script outputs will be compressed. The shell script will be run from inside the package build directory. Note though that using -X is a
	   much better idea in general; you should only use a debian/package.compress file if you really need to.

OPTIONS

       -Xitem, --exclude=item
	   Exclude files that contain item anywhere in their filename from being compressed. For example, -X.tiff will exclude TIFF files from
	   compression.  You may use this option multiple times to build up a list of things to exclude.

       -A, --all
	   Compress all files specified by command line parameters in ALL packages acted on.

       file ...
	   Add these files to the list of files to compress.

CONFORMS TO

       Debian policy, version 3.0

SEE ALSO

       debhelper(7)

       This program is a part of debhelper.

AUTHOR

       Joey Hess <joeyh@debian.org>

9.20120909							    2012-05-19							    DH_COMPRESS(1)
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