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I know you're wanting to do this in perl but leveraging sed will do the job a lot easier. &nbsp;I've just tested the following: 
 
cat group | sed 's/sdb,sdb,david,sdb/david/g' 
 
Returns: 
 
sdba::1014:david 
 
Also using egrep for the beginning of line ^sdba and piping to sed works the same 
 
egrep ^sdba group | sed 's/sdb,sdb,david,sdb/david/g'
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I could use sed, because the actual executable is a ksh script. &nbsp;The problem with this is it might not be &quot;david&quot;. &nbsp;It might be any other name. &nbsp;I just want to get rid of the &quot;sdb&quot; entries, of couse leaving the group name of sdba. 
 
Thanks! 
David
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And, it needs to only make the change on the sdba line. &nbsp;&quot;sdb&quot; might be under another group, and I would want that to stay.
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Wow, I was really overthinking this one. I was about to go to Python. Thanks! 
David
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Thanks again! Sometimes I need to just get up and walk away. 
 
David
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Sorry to be the bearer of bad news, but Travis's solution will not handle cases like this: 
$ cat group 
sdba::1014:sdb,sdb,david,sdb 
sdba::1015:sdb,test2,david,sdb 
sdbb::1016:test1,test2,david,sdb 
 
Here's what happens: 
$ egrep ^sdba group | sed 's/sdb//g' | sed 's/,//g' | sed 's/a::/sdba::/g' 
sdba::1014:david 
sdba::1015:test2david 
 
Note how there is no comma between test2 &amp;&nbsp;david. 
ozo's 2nd Perl solution doesn't have this problem. 
 
Also, commands like this: 
&nbsp; &nbsp; cat group | sed 's/sdb,sdb,david,sdb/david/g' 
can be simplified to this (no cat, pipe and in this case I doubt the /g would be necessary): 
&nbsp; &nbsp; sed 's/sdb,sdb,david,sdb/david/' group 
 
And commands like this: 
&nbsp; &nbsp; egrep ^sdba group | sed 's/sdb//g' | sed 's/,//g' | sed 's/a::/sdba::/g' 
can be simplified to this (no need for egrep when grep will work, and remove some pipes and seds): 
&nbsp; &nbsp; grep ^sdba group | sed 's/sdb//g; s/,//g; s/a::/sdba::/g' 
and maybe even this (no grep): 
&nbsp; &nbsp; sed '/^sdba/ {s/sdb//g;s/,//g;s/a::/sdba::/g}' group 
although the latter retains lines which don't start with &quot;sdba&quot;. 
 
Questions for David: 
Q1. When you said this: 
 &nbsp; &nbsp;&quot;If I have the following line in my group file...&quot; 
you didn't state what the line was. &nbsp;What was it? &nbsp;Anything starting with &quot;sdba:&quot;? 
Q2. What did you want to happen with the lines which didn't start with &quot;sdba&quot;? &nbsp;Remove them completely or leave them intact? 
Q3. And did you want to overwrite the original file, as your use of Perl's -i switch suggests, or what? 
 
Here's a simpler Perl solution, but whether it does what you want depends on your answers to my questions above: 
&nbsp; &nbsp; perl -pe &nbsp;'/^sdba:/ &amp;&amp;&nbsp;s/,sdb|sdb,//g' group 
Or in sed: 
&nbsp; &nbsp; sed '/^sdba:/ {s/,sdb//g; s/sdb,//g}' group 
The output of these can differ from ozo's 2nd Perl solution. &nbsp;For example, for this input: 
&nbsp; &nbsp; sdba:sdb:1012:test1,sdb,sdb,david 
my Perl &amp;&nbsp;sed solutions above would output this: 
&nbsp; &nbsp; sdba:sdb:1012:test1,david 
and ozo's would output this: 
&nbsp; &nbsp; sdba::1012:test1,david 
But that kind of input may never happen so it may not make any difference.
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What should the result be from 
sdba::1014:sdb1,test1,sdb,sdba,sdb,david,testsdb 
?
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sdba::1014:sdb1,test1,sdba,david,testsdb &nbsp; 
 
Although, I would never see anything like that. &nbsp;Here's the most radical example that I've tested it with and it works fine so far: 
 
sdba::1014:sdb,sdb,david,sdb,billy,sdb,sue,sdb 
 
ends up: 
 
sdba::1014:david,billy,sue
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Hi David, 
 
ozo seems to be demonstrating a shortcoming of your latest solution. &nbsp;You've said above that this: 
&nbsp; &nbsp; sdba::1014:sdb1,test1,sdb,sdba,sdb,david,testsdb 
should become this: 
&nbsp; &nbsp; sdba::1014:sdb1,test1,sdba,david,testsdb 
but as you can see when you process it: 
&nbsp; &nbsp; echo &quot;sdba::1014:sdb1,test1,sdb,sdba,sdb,david,testsdb&quot; | grep &quot;^sdba&quot; | sed 's/:sdb/:/g' | sed 's/,sdb,/,/g' | sed 's/sdb$//g' | sed 's/,$//g' | sed 's/:,/:/g' 
it becomes this: 
&nbsp; &nbsp; sdba::1014:1,test1,sdba,david,test 
which is quite different. 
 
That kind of input may not happen, but maybe something like this is more realistic: 
&nbsp; &nbsp; echo &quot;sdba::1014:sdbb,sdb,sdb,david&quot; | grep &quot;^sdba&quot; | sed 's/:sdb/:/g' | sed 's/,sdb,/,/g' | sed 's/sdb$//g' | sed 's/,$//g' | sed 's/:,/:/g' 
Here's the output you'd get: 
&nbsp; &nbsp; sdba::1014:b,sdb,david 
That &quot;b&quot; ain't pretty, is it? 
 
I suggest you go for one of the shorter, more robust, and possibly simpler solutions provided by ozo or myself. &nbsp;Here are mine again: 
&nbsp; &nbsp; perl -pe &nbsp;'/^sdba:/ &amp;&amp;&nbsp;s/,sdb|sdb,//g' group 
Or in sed: 
&nbsp; &nbsp; sed '/^sdba:/ {s/,sdb//g; s/sdb,//g}' group 
Or here's a slightly different version: 
&nbsp; &nbsp; perl -pe &nbsp;'s/,sdb|sdb,//g if /^sdba:/' group 
If there's some reason those aren't what you want, please explain why and we might be able to sort it out. 
 
Also, what were the answers to my <a href="https://www.experts-exchange.com/questions/29087372/Replacing-words-in-a-line-of-a-file.html?anchorAnswerId=42490887#a42490887" rel="ugc">questions</a> Q1-Q3, David?
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Thank you for the continued interest. &nbsp;While I'm sure that what I have would WORK, it most certainly, as you point out, isn't the best solution. &nbsp;In the real world, I'm most likely going to only want to get rid of the &quot;sdb&quot; user if it is attached to the sdba group. &nbsp;I really don't see any others being in there, but I was just trying to take that into account. I think I will do as you suggest and work with one of the better solutions that you've suggested, just in case! &nbsp;The answers to your questions are: 
 
1. &nbsp;The exact line I originally put down, although &quot;david&quot; was added as a test: &nbsp; sdba::1014:sdb,sdb,david,sdb 
2. &nbsp;I don't want to do anything to a line that doesn't start with sdba, i.e., ^sdba: 
3. &nbsp;I took this project over from someone else who has been working on it for a while and needed help so I was starting to work with what he already had there. &nbsp;What I ended up doing with the sed solution is writing to a temp file and I'll just copy rename it when the process is over. 
 
Again, thanks for your help. &nbsp;I wish I could give you and ozo some points on it. &nbsp;I was just in a hurry and jumped at the first thing that worked with my original request. 
 
Thanks, 
David
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<div>
So if you're interested, this whole question was actually part of a do while loop in ksh. &nbsp;It does quite a bit to the group file. &nbsp;Here's the entire loop. &nbsp;It's working as it is, but the &quot;sdba&quot; and &quot;dazel&quot; pieces were the biggest problem. &nbsp;I'm sure this could be done a LOT easier and more efficient than what I came up with: 
 
&nbsp; &nbsp; &nbsp; &nbsp; TEMP=&quot;temp&quot;$(date '+%d%m%Y') 
&nbsp; &nbsp; &nbsp; &nbsp; touch $TEMP 
 
&nbsp; &nbsp; &nbsp; &nbsp; while read line 
&nbsp; &nbsp; &nbsp; &nbsp; do 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if [[ $(echo $line|grep &quot;mysql::70:&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; MYSQL=found 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $line &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; elif [[ $(echo $line | grep &quot;^mlocate&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; MLOCATE=found 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $line &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; elif [[ $(echo $line | grep &quot;^slocate&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; continue 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; elif [[ $(echo $line | grep &quot;^sdba&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $line |grep &quot;^sdba&quot; | sed 's/:sdb/:/g' | sed 's/,sdb,/,/g' | sed 's/sdb$//g' | sed 's/,$//g' | sed 's/:,/:/g' &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; elif [[ $(echo $line | grep &quot;^dazel&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $line |grep &quot;^dazel&quot; | sed 's/:dazel/:/g' | sed 's/,dazel,/,/g' | sed 's/dazel$//g' | sed 's/,$//g' | sed 's/:,/:/g' &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; else 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; grep -q &quot;$line&quot; $TEMP || echo $line &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fi 
&nbsp; &nbsp; &nbsp; &nbsp; done &lt;&nbsp;/etc/group 
&nbsp; &nbsp; &nbsp; &nbsp; [ ! $MYSQL ] &amp;&amp;&nbsp;echo &quot;mysql::70:&quot; &gt;&gt;&nbsp;$TEMP 
&nbsp; &nbsp; &nbsp; &nbsp; [ ! $MLOCATE ] &amp;&amp;&nbsp;echo mlocate::95: &gt;&gt;&nbsp;$TEMP 
 
&nbsp; &nbsp; &nbsp; &nbsp; # mv $TEMP /etc/group
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<div>
Done. &nbsp;We'll see what the moderators say. &nbsp;Considering the expanse of the question, I would think it would be acceptable for me to open another question, posting the entire loop. &nbsp;You and ozo have been a great help.
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<div>
Sorry about all of the point shuffling guys. &nbsp;I really appreciate all of the help you gave. &nbsp;I also could have been much clearer in my original question. &nbsp;I ended up using this line from tel2's comment: 
 
echo $line | sed 's/,sdb//g; s/sdb,//g' &gt;&gt;&nbsp;$TEMP
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<div>
Thanks, David. 
 
Did you also use this line that I also suggested?: 
&nbsp; &nbsp; echo $line | sed 's/,dazel//g; s/dazel,//g' &gt;&gt;&nbsp;$TEMP 
 
Why do you feel the need to open another question? &nbsp;Do you need more help?
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<div>
For the &quot;dazel&quot; entry, I just used the one below because there would only ever be dazel::206:dazel &nbsp; There shouldn't be ANY users with dazel as a secondary group. &nbsp;Now that I think about it, I guess I could just overwrite the line with dazel::206: no matter what's there. &nbsp;But here's what I used: 
 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; elif [[ $(echo $line | grep &quot;^dazel&quot;) ]] 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; then 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $line | sed 's/:dazel/:/g' &gt;&gt;&nbsp;$TEMP 
 
The reason I mentioned possibly opening another question was because I closed this one too quickly and received so much more help from you and ozo that I wanted to be able to reward points to the both of you as well. &nbsp;Your suggestion worked and they let me reopen it though. &nbsp;Thanks once again! 
 
David
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OK David, I guess that will work, but technically you don't need the /g (global replace), because you're replacing the 1st (and only) match alone. &nbsp;So this: 
&nbsp; &nbsp; echo $line | sed 's/:dazel/:/g' &gt;&gt;&nbsp;$TEMP 
Could change to this: 
&nbsp; &nbsp; echo $line | sed 's/:dazel/:/' &gt;&gt;&nbsp;$TEMP
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<div class="content wysiwyg-content">
replacing parts of a line in a file (/etc/group). 
 
If I have the following line in my group file, I want to remove all of the &quot;sdb&quot; entries, but leave anything else. &nbsp;For instance: 
 
sdba::1014:sdb,sdb,david,sdb 
 
would need to be changed to: 
 
sdba::1014:david 
 
I'm trying to do this with perl -pi -e if I can. &nbsp;This SORT of gets me there, but removes the &quot;david&quot; entry. 
 
egrep &quot;^sdba:&quot; $TEMP &amp;&amp;&nbsp;perl -pi -e &quot;s/^sdba::.*/sdba::1014:/g&quot; $TEMP 
 
Thanks! 
David
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</div>

replacing parts of a line in a file (/etc/group).

If I have the following line in my group file, I want to remove all of the "sdb" entries, but leave anything else.  For instance:

sdba::1014:sdb,sdb,david,sdb

would need to be changed to:

sdba::1014:david

I'm trying to do this with perl -pi -e if I can.  This SORT of gets me there, but removes the "david" entry.

egrep "^sdba:" $TEMP && perl -pi -e "s/^sdba::.*/sdba::1014:/g" $TEMP

Thanks!
David

Replacing words in a line of a file.

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