Have a look here http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion or google "parameter expansion bash" (or ksh)
From: peterboro-boun...@mailman.lug.org.uk [mailto:peterboro-boun...@mailman.lug.org.uk] On Behalf Of Richard Forth Sent: 03 May 2012 17:15 To: Peterborough LUG - No commercial posts Subject: Re: [Peterboro] BASH CODING: Bulk User and Group Adder See below :) On 3 May 2012 16:32, COX Derek <derek....@alstom.com<mailto:derek....@alstom.com>> wrote: You may well find you generate a bunch of contradictory ideas about style, efficiency over simplicity etc Oh, and some people can get mighty pedantic too :) Constructive observations - Why assign $# to argcount rather than just checking $# ? Good point, This could have been much shorter, but I kind of like this way of doing things as it documents itself, not everyone knows what $# means, but "argcount = $#" says it all. You are right though If concise code is the key, then documentation is often not an issue. Point taken all the same, I just do things this way. - Error checking missing after commands (eg groupadd, useradd) True, but thats why I added the syscheck output - as I didn't really know how to do this bit - Consider shell substitution to get group and members rather than two new awk processes group=${line%%:*} members=${line##*:} Wow - can you explain these!! They look awesome! - Reconsider `groups $member | grep -q $group` - it will match superstrings of the group. Eg "groups | grep sales" would match group "salesman". grep -wq should do it. (or a user called lesales ......) Hmm I hear you, the original code was something like this: grep -c ^$group: so that wasnt a problem before i hacked up the condition tests.. Good luck ;) Thanks for your feedback, you've added at least 50% more awesomeness to my coding skills (can you just explain those regexes for me in the shell substitition?). Always good to get some criticisms, makes me a better coder in the end :) From: peterboro-boun...@mailman.lug.org.uk<mailto:peterboro-boun...@mailman.lug.org.uk> [mailto:peterboro-boun...@mailman.lug.org.uk<mailto:peterboro-boun...@mailman.lug.org.uk>] On Behalf Of Richard Forth Sent: 03 May 2012 15:28 To: Peterborough LUG - No commercial posts Subject: Re: [Peterboro] BASH CODING: Bulk User and Group Adder Aaargh - new version!! http://pastebin.com/yL2pvayv Corrected a schoolboy error for line in `cat bugalist` to for line in `cat $1` On 3 May 2012 15:25, Richard Forth <richard.fo...@gmail.com<mailto:richard.fo...@gmail.com>> wrote: Thanks Jonathan, I've incorporated your suggestions in a new version: http://pastebin.com/v9k27RSA Cheers! Richard On 3 May 2012 15:07, Johnathon Tinsley <johnat...@positive-internet.com<mailto:johnat...@positive-internet.com>> wrote: Hi Richard, Really quick scan, but it looks like you're loading a variable to run a if on, basing it on grep (line 16 etc). You can do this directly, so something like: if grep -q ^$group: /etc/group; then echo "found one or more!" else; echo "didn't find any :(" fi The -q means grep is quiet, only returning via exit codes. Relevant man page snippet: -q, --quiet, --silent Quiet; do not write anything to standard output. Exit immediately with zero status if any match is found, even if an error was detected. Also see the -s or --no-messages option. (-q is specified by POSIX.) HTH, Johnathon On 03/05/12 14:43, Richard Forth wrote: > Hi Peeps, > > I wanted to share with you a working BASH script that basically takes a > textfile that looks kinda like this: > > sales:mark,sally,dave,sue,steve > marketing:jason,philip,eric,steve > ... > > and processes each line - lets take the first line as example: > > Checks to see if sales exists already in /etc/group > If not creates it. > then checks to see if each user exists, if they do > it checks to see if they are already in the group, > if not it adds it to the group > if the user doesnt exist it creates the user and assigns a random 8 > character password, then adds it to the group. > If you want one particular user to be in more than one group thats ok > just add it to whatever line for that group (see steve in the example). > > Its only 49 lines of code, including documentation notes. > > Probably totally impractical in real life but it was an exercise in bash > coding, with this aim in mind. > > If anyone wants a copy, I've created a public pastebin: > http://pastebin.com/uPxsZcGr > > the textfile was originally called bugalist > > > 8 for line in `cat bugalist` > > > You can probably modify line 8 to be $1 or set up some code to check for > arguments etc, which I now realise I missed out, and didnt document > either (damn). > > Anyway just in case you wonder what "bugalist" was: > > ~/Dev_Area/bash $ cat bugalist > u5:john,tessa,richard,steve > u6:dorris,erran,jason,steve > ~/Dev_Area/bash $ > > Sample output: > ~/Dev_Area/bash $ sudo ./buga > =========== > Processing Line: > u5:john,tessa,richard,steve > =========== > Creating group 'u5' ... > Members: john,tessa,richard,steve > Creating user 'john' ... > Password for user 'john' set to: vM6oElDG > Adding user 'john' to group 'u5' ... > uid=1002(john) gid=1003(john) > groups=1003(john),1002(u5) > > Creating user 'tessa' ... > Password for user 'tessa' set to: t9jt2uRR > Adding user 'tessa' to group 'u5' ... > uid=1003(tessa) gid=1004(tessa) > groups=1004(tessa),1002(u5) > > Creating user 'richard' ... > Password for user 'richard' set to: vZddQN4g > Adding user 'richard' to group 'u5' ... > uid=1004(richard) gid=1005(richard) > groups=1005(richard),1002(u5) > > Creating user 'steve' ... > Password for user 'steve' set to: RG8fdZjG > Adding user 'steve' to group 'u5' ... > uid=1005(steve) gid=1006(steve) > groups=1006(steve),1002(u5) > > =========== > Processing Line: > u6:dorris,erran,jason,steve > =========== > Creating group 'u6' ... > Members: dorris,erran,jason,steve > Creating user 'dorris' ... > Password for user 'dorris' set to: qDTgCcxn > Adding user 'dorris' to group 'u6' ... > uid=1006(dorris) gid=1008(dorris) > groups=1008(dorris),1007(u6) > > Creating user 'erran' ... > Password for user 'erran' set to: JOL47SrN > Adding user 'erran' to group 'u6' ... > uid=1007(erran) gid=1009(erran) > groups=1009(erran),1007(u6) > > Creating user 'jason' ... > Password for user 'jason' set to: 3UG416G6 > Adding user 'jason' to group 'u6' ... > uid=1008(jason) gid=1010(jason) > groups=1010(jason),1007(u6) > > User 'steve' already exists. > Adding user 'steve' to group 'u6' ... > uid=1005(steve) gid=1006(steve) > groups=1006(steve),1002(u5),1007(u6) > > > Enjoy! > > Feedback welcome. > > Enjoy! > Rich > > > > > > > _______________________________________________ > Peterboro mailing list > Peterboro@mailman.lug.org.uk<mailto:Peterboro@mailman.lug.org.uk> > https://mailman.lug.org.uk/mailman/listinfo/peterboro -- All postal correspondence to: The Positive Internet Company, 24 Ganton Street, London. 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