10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
I am having a file as stated below :
File 1:
##########################
idnd a
integer 2;
list 1 ;
list2 ;
chip top alist( .a(1) , .b(2) , .c(3) ,
.d(1) , .e(7) , .n(80),
.d(1) , .g(7) , .n(80),
.f(1) , .e(7) , .m(80));
lis 7 nfj ;
jdjd kn;
jsjd l ; (4 Replies)
Discussion started by: kshitij
4 Replies
2. Shell Programming and Scripting
Hi ,
i am stuck in this simple script.
#!/bin/ksh
echo "enter the file name"
read flname
echo "enter version"
read ver
grep $flname /home/con/snsc/perl/map > flplist
dirname `cat flplist` | sed 's/\/so${vers}\//\/so${vers}_xyz\//' > dirlist
the map file is basically a list of file... (3 Replies)
Discussion started by: debu182
3 Replies
3. Shell Programming and Scripting
I am beginner for Unix. I practicing unix shell script. I worked out some sed script example from internet. Everything fine.
But in real unix environment, where sed script is mainly used.?
Can anyone give some examples for the usage of sed script in real unix environment. It will be useful for... (1 Reply)
Discussion started by: gwgreen1
1 Replies
4. Homework & Coursework Questions
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
Create a sed script that will display a list of all users in the /etc/passwd file that belong to the group... (0 Replies)
Discussion started by: lakers34kb
0 Replies
5. Shell Programming and Scripting
I'm trying to write a simple script that replaces a string. The script works for uninterrupted strings, but as soon as sed encounters a space it stops reading the new string. I've tried double quotations in sed and backslashes before the $, however these don't work. Below is the script. Any help... (9 Replies)
Discussion started by: dsell002
9 Replies
6. UNIX for Dummies Questions & Answers
:rolleyes:
I have a series of folders /temp/a /temp/b /temp/c
In folders a, b, and c, I have files
a1.txt..........a20.txt
b1.txt..........b40.txt &
c1.txt..........c60.txt
Each file has the same data format :-
Line... (2 Replies)
Discussion started by: grinder182533
2 Replies
7. Shell Programming and Scripting
how to convert the follow sed script file into a command line ?
example:
/^\.TS/,/^\.TE/{
/^$/p
}
I have tried the below but it is not working:
# sed -n "/^\.TS/,/^\.TE/{/^$/p}" file
file:
111
.TS
222
$333 << extract this line
444
.TE
555 (2 Replies)
Discussion started by: 3Gmobile
2 Replies
8. Shell Programming and Scripting
I am trying to run a sed command within a script to edit a file.
I am trying to put the value of MYUSER into the sshd_config file.
Instead of putting the value of the variable, MYUSER, it puts in the string ${MYUSER}.
Anyone know a good solution to this?
cat ${SSHD_CONFIG} | sed... (1 Reply)
Discussion started by: Mike_the_Man
1 Replies
9. Shell Programming and Scripting
/\/\*/!b
:x
/\*\//!{
N
bx
}
s/\/\*.*\*\///
This scipt should remove c like commnets /**/
i know what de last line does
but i dont't know what the first lines do
Can anyone explain please (3 Replies)
Discussion started by: clauchiorean
3 Replies
10. Shell Programming and Scripting
I have a lot of script files that were created by Extract in a dir that no longer exists. Now that I have to run these scripts they 'all' have to be changed. I'm looking for a way to do a 'mass' change if possible.
So far, I've dumped all of the script file names to a file and sorted them to... (5 Replies)
Discussion started by: HOlli
5 Replies
A2P(1) Perl Programmers Reference Guide A2P(1)
NAME
a2p - Awk to Perl translator
SYNOPSIS
a2p [options] [filename]
DESCRIPTION
A2p takes an awk script specified on the command line (or from standard input) and produces a comparable perl script on the standard
output.
OPTIONS
Options include:
-D<number>
sets debugging flags.
-F<character>
tells a2p that this awk script is always invoked with this -F switch.
-n<fieldlist>
specifies the names of the input fields if input does not have to be split into an array. If you were translating an awk script that
processes the password file, you might say:
a2p -7 -nlogin.password.uid.gid.gcos.shell.home
Any delimiter can be used to separate the field names.
-<number>
causes a2p to assume that input will always have that many fields.
-o tells a2p to use old awk behavior. The only current differences are:
o Old awk always has a line loop, even if there are no line actions, whereas new awk does not.
o In old awk, sprintf is extremely greedy about its arguments. For example, given the statement
print sprintf(some_args), extra_args;
old awk considers extra_args to be arguments to "sprintf"; new awk considers them arguments to "print".
"Considerations"
A2p cannot do as good a job translating as a human would, but it usually does pretty well. There are some areas where you may want to
examine the perl script produced and tweak it some. Here are some of them, in no particular order.
There is an awk idiom of putting int() around a string expression to force numeric interpretation, even though the argument is always
integer anyway. This is generally unneeded in perl, but a2p can't tell if the argument is always going to be integer, so it leaves it in.
You may wish to remove it.
Perl differentiates numeric comparison from string comparison. Awk has one operator for both that decides at run time which comparison to
do. A2p does not try to do a complete job of awk emulation at this point. Instead it guesses which one you want. It's almost always
right, but it can be spoofed. All such guesses are marked with the comment ""#???"". You should go through and check them. You might
want to run at least once with the -w switch to perl, which will warn you if you use == where you should have used eq.
Perl does not attempt to emulate the behavior of awk in which nonexistent array elements spring into existence simply by being referenced.
If somehow you are relying on this mechanism to create null entries for a subsequent for...in, they won't be there in perl.
If a2p makes a split line that assigns to a list of variables that looks like (Fld1, Fld2, Fld3...) you may want to rerun a2p using the -n
option mentioned above. This will let you name the fields throughout the script. If it splits to an array instead, the script is probably
referring to the number of fields somewhere.
The exit statement in awk doesn't necessarily exit; it goes to the END block if there is one. Awk scripts that do contortions within the
END block to bypass the block under such circumstances can be simplified by removing the conditional in the END block and just exiting
directly from the perl script.
Perl has two kinds of array, numerically-indexed and associative. Perl associative arrays are called "hashes". Awk arrays are usually
translated to hashes, but if you happen to know that the index is always going to be numeric you could change the {...} to [...].
Iteration over a hash is done using the keys() function, but iteration over an array is NOT. You might need to modify any loop that
iterates over such an array.
Awk starts by assuming OFMT has the value %.6g. Perl starts by assuming its equivalent, $#, to have the value %.20g. You'll want to set
$# explicitly if you use the default value of OFMT.
Near the top of the line loop will be the split operation that is implicit in the awk script. There are times when you can move this down
past some conditionals that test the entire record so that the split is not done as often.
For aesthetic reasons you may wish to change index variables from being 1-based (awk style) to 0-based (Perl style). Be sure to change all
operations the variable is involved in to match.
Cute comments that say "# Here is a workaround because awk is dumb" are passed through unmodified.
Awk scripts are often embedded in a shell script that pipes stuff into and out of awk. Often the shell script wrapper can be incorporated
into the perl script, since perl can start up pipes into and out of itself, and can do other things that awk can't do by itself.
Scripts that refer to the special variables RSTART and RLENGTH can often be simplified by referring to the variables $`, $& and $', as long
as they are within the scope of the pattern match that sets them.
The produced perl script may have subroutines defined to deal with awk's semantics regarding getline and print. Since a2p usually picks
correctness over efficiency. it is almost always possible to rewrite such code to be more efficient by discarding the semantic sugar.
For efficiency, you may wish to remove the keyword from any return statement that is the last statement executed in a subroutine. A2p
catches the most common case, but doesn't analyze embedded blocks for subtler cases.
ARGV[0] translates to $ARGV0, but ARGV[n] translates to $ARGV[$n-1]. A loop that tries to iterate over ARGV[0] won't find it.
ENVIRONMENT
A2p uses no environment variables.
AUTHOR
Larry Wall <larry@wall.org>
FILES
SEE ALSO
perl The perl compiler/interpreter
s2p sed to perl translator
DIAGNOSTICS
BUGS
It would be possible to emulate awk's behavior in selecting string versus numeric operations at run time by inspection of the operands, but
it would be gross and inefficient. Besides, a2p almost always guesses right.
Storage for the awk syntax tree is currently static, and can run out.
perl v5.14.2 2010-12-30 A2P(1)