Need a script to edit text of file

[cavinsays]

Hi,

So the exact situation is that I need to edit my .profile (I'm on OS X) a lot. I have two lines (lines 48 and 49) which I have to alternate.

So I'll have to open nano every time I want to uncomment 48 and comment out 49 and vice versa. It gets a bit redundant and tedious after a while.

Is there a command or script that could help me do this? I tried looking at how to use awk/cut/perl, but I don't really have time to learn an entire scripting language.

Thanks,

Cavin

[GNU-Fan]

A quick way to do this without sed/awk is two have two separate template files and copy the appropriate one to its destination.

[infinitiguy]

A quick way to do this without sed/awk is two have two separate template files and copy the appropriate one to its destination.

This would work, and you'd just have to re-source your profile.

I do something similar, where I edit my profile alot.. so I have an alias to vi to edit my profile.. and then another alias to resource my profile.

alias epro='vi /home/dmurphy/.profile'
alias rs='source /home/dmurphy/.profile'

You could make this all a function so if you're just swapping the two.. you could do something like this (if then syntax could be wrong.. just doing this in my head logically..)
usage would be swappro 1 or swappro 2

function swappro () {

if [ $1 == 1 ] then;
{
cp <pathToProfile>/profile1 <pathToProfile>/profile
source <pathToProfile>/profile
}
elseif { $1 == 2 ] then;
{
cp <pathToProfile>/profile2 <pathToProfile>/profile
source <pathToProfile>/profile
}
fi
}

[Cabhan]

This can also be done by using awk. For instance:

#!/usr/bin/awk

if (((NR == 48) || (NR == 49)) && /^#/)
    print substr($0, 1, length($0));
else if((NR == 48) || (NR == 49))
    print "#" $0;

This will look at lines 48 and 49 of the file it is applied to and will prepend a "#" if there is none already, and remove the "#" at the beginning if there is one.

There are some obvious deficiencies, which is that 48 and 49 are hardcoded. However, that is easily fixable by changing it to accept the lines as arguments.

I also believe that this is a bit superior to the option of multiple profiles because only two lines are affected. With this method, you only need to change your profile in one location, whereas if you keep separate files, you have to make changes in both of them.

[infinitiguy]

excellent solution Cabhan.

That's what I originally wanted to post.. but I wasn't sure exactly how to simply put it, without using awk/sed and creating a large script, which would've taken me time to figure out.

The 2 profiles solution is a yucky one at best.

[cavinsays]

This can also be done by using awk. For instance:

#!/usr/bin/awk

if (((NR == 48) || (NR == 49)) && /^#/)
    print substr($0, 1, length($0));
else if((NR == 48) || (NR == 49))
    print "#" $0;

This will look at lines 48 and 49 of the file it is applied to and will prepend a "#" if there is none already, and remove the "#" at the beginning if there is one.

There are some obvious deficiencies, which is that 48 and 49 are hardcoded. However, that is easily fixable by changing it to accept the lines as arguments.

I also believe that this is a bit superior to the option of multiple profiles because only two lines are affected. With this method, you only need to change your profile in one location, whereas if you keep separate files, you have to make changes in both of them.

Thank you.

I may just be lost on the syntax of how to use it. I tried it like:

./chprof.awk .profile

while being in my home directory, but it gives me:

/usr/bin/awk: syntax error at source line 1
 context is
	 >>> . <<< /chprof

What am I missing?

[Cabhan]

So I in fact did not test the program I posted here before, and I am not as powerful an awk guru as others, so it doesn't in fact fully work. Sorry about that. This one should work (and you can run it with the ./ syntax like you tried):

#!/usr/bin/awk -f

line1 = 48
line2 = 49

(((NR == line1) || (NR == line2)) && /^#/) {
    print substr($0, 2, length($0))
    next
}

(((NR == line1) || (NR == line2))) {
    print "#" $0
    next
}

I have also turned the line numbers into variables, so they should be simple to change if your profile changes.

Also note that this does not actually make one line commented and the other uncommented. Instead, it looks at these two lines and comments them if they are uncommented, and uncomments them if they are commented. Therefore, you can easily get this script to not work entirely as intended, but as long as you don't change the commenting of the lines on your own, this should work fine.

Sorry about the screwy solution earlier. Hope this helps!

[cavinsays]

So I in fact did not test the program I posted here before, and I am not as powerful an awk guru as others, so it doesn't in fact fully work. Sorry about that. This one should work (and you can run it with the ./ syntax like you tried):

#!/usr/bin/awk -f

line1 = 48
line2 = 49

(((NR == line1) || (NR == line2)) && /^#/) {
    print substr($0, 2, length($0))
    next
}

(((NR == line1) || (NR == line2))) {
    print "#" $0
    next
}

I have also turned the line numbers into variables, so they should be simple to change if your profile changes.

Also note that this does not actually make one line commented and the other uncommented. Instead, it looks at these two lines and comments them if they are uncommented, and uncomments them if they are commented. Therefore, you can easily get this script to not work entirely as intended, but as long as you don't change the commenting of the lines on your own, this should work fine.

Sorry about the screwy solution earlier. Hope this helps!

Thank you for the effort though! It's appreciated.

Unfortunately now, it doesn't seem to be doing anything at all... When I run it:

./chprof.awk .profile

(in my home dir btw)

it prints the contents of my .profile, but each line is printed twice.

So, for example, I have an alias:

alias texmate='open -a TextMate'

and it prints:

alias texmate='open -a TextMate'
alias texmate='open -a TextMate'

[drl]

Hi.

Modified awk code as follows:

#!/usr/bin/env bash

# @(#) s1	Demonstrate toggle commenting lines.

# Infrastructure details, environment, commands for forum posts. 
set +o nounset
LC_ALL=C ; LANG=C ; export LC_ALL LANG
echo ; echo "Environment: LC_ALL = $LC_ALL, LANG = $LANG"
echo "(Versions displayed with local utility \"version\")"
c=$( ps | grep $$ | awk '{print $NF}' )
version >/dev/null 2>&1 && s=$(_eat $0 $1) || s=""
[ "$c" = "$s" ] && p="$s" || p="$c"
version >/dev/null 2>&1 && version "=o" $p awk
set -o nounset
echo

echo " awk procedure a1:"
cat a1

FILE=${1-data1}

echo
echo " Data file $FILE:"
cat $FILE

echo
echo " Results:"
./a1 $FILE

exit 0

producing:

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0 
GNU bash 3.2.39
GNU Awk 3.1.5

 awk procedure a1:
#!/usr/bin/awk -f

BEGIN	{ line1 = 2 ; line2 = 3 }

(((NR == line1) || (NR == line2)) && /^#/) {
    print substr($0, 2, length($0))
    next
}

(((NR == line1) || (NR == line2))) {
    print "#" $0
    next
}

	{ print }

 Data file data1:
foo
#bar
baz
qux

 Results:
foo
bar
#baz
qux

Best wishes ... cheers, drl