Pattern matching from the input arguments

regular-expression ksh string arguments

7,300

Solution 1

Pattern matching in POSIX shells is done with the case construct. ksh also as the [[ x = pattern ]] operator (also copied by bash and zsh) and [[ x =~ regexp ]] in recent versions.

So:

case $1 in
  (*5.0.3*)
    install=$1.tar
    echo Found;;
  (*)
    echo >&2 Not found
    exit 1;;
esac

Solution 2

I'm not an expert at regular expressions, but this works, at least for what you described.

#!/bin/sh

argument="$1"

#if [[ $argument =~ [a-zA-Z]*5\.0\.3[a-zA-Z]+ ]]; then# only works on bash
if echo $argument | egrep -q '[a-zA-Z]*5\.0\.3[a-zA-Z]+'; then
  #echo "Found: ${BASH_REMATCH[0]}" # for bash
  echo "Match Found"

  # you can check for $argument at some other location, here.

else
  echo "No match"
fi

Saving it as test and running it, gives the following results:

bash test 333xxxx5.0.3xxxxx777
Match Found

bash test 333xxxx5.0.2xxxxx777
No match

bash test 5.0.3xxxxx777
Match Found

bash test 5.0.2xxxxx777
No match

You can add ^ at the beginning and $ at the end, to match the full string or nothing. Like this ^[a-zA-Z]*5\.0\.3[a-zA-Z]+$

7,300

Author by

user31522

Updated on September 18, 2022

Comments

user31522 over 1 year
We're trying to enhance one of our scripts.

Users will pass some arguments and part of the arguments will have 5.0.3. For an example, the input argument would be like Jboss5.0.3GA. Since it ( Jboss5.0.3GA ) has "5.0.3" we'll try to locate the installation binary file "Jboss5.0.3GA.tar".

The current script we've now is a ksh script. I'm trying to use an if condition with the script.

Sample use cases and results:
```
./test.sh Jboss5.0.3GA
Match found... we'll try to locate the installation binary
./test.sh Jboss5.0.3
Match found... we'll try to locate the installation binary
./test.sh 5.0.3
Match found... we'll try to locate the installation binary
./test.sh Jboss5.1.3
No Match found ... we'll be exiting the script.
```
- Bernhard over 11 years
  
  I have no clue what you want. I think it is not me, but the way you ask the question. Can you clarify a bit? Be more specific in input and desired behavior? Also, what have you tried?
- user31522 over 11 years
  
  I've one of my script and looking for enhancing it.
- user31522 over 11 years
  
  So users running the scripts will pass some arguments while running the script like jboss5.0.3GA ( = xxxx5.0.3xxx). So when I see 5.0.3 as as part of their input ( sometimes they can pass 5.0.3jboss ) all I'd need is to lookup for that string 5.0.3 in their input argument ...then I'd need to lookup for the file name at some location. Filename would be Jboss5.0.3GA.tar. If they do pass 5.0.3 as a part of their input argument I'll throw an error with usage function which will tell the users to pass the right arguments.... Thanks so much for the prompt response!
- user31522 over 11 years
  
  small correction in my previous post:If they donot* pass 5.0.3 as a part of their input argument I'll throw an error with usage function which will tell the users to pass the right arguments
user31522 over 11 years

Thanks so much again for the prompt response ...I'm getting the error code./test2.bash jboss5.0.3fds ./test2.bash: line 5: conditional binary operator expected ./test2.bash: line 5: syntax error near =~' ./test2.bash: line 5: if [[ $argument =~ ^[a-zA-Z]*5\.0\.3[a-zA-Z]+$ ]]; then'code
user31522 over 11 years

I've tried to use = , == and ran it passing jboss5.0.3fds but getting the result as No Match ...
lmcanavals over 11 years

What OS are you running and do you have bash installed at all? the "=~" operator is bash specific. Let me know if that is a problem I'll see what I can do.
user31522 over 11 years

Hi Martin Canaval, Thanks so much sir for your assistance! I'm on LinuxcodeLinux 2.6.5-7.308-bigsmp #1 SMP Mon Dec 10 11:36:40 UTC 2007 i686 i686 i386 GNU/Linuxcode
lmcanavals over 11 years

I made some changes that should work on ksh.
user31522 over 11 years

Looks like we've it bash-2.05b-305.18 ... which bash /bin/bash
Mikel over 11 years

The =~ operator was introduced in bash 3.0. Maybe OP has bash 2.05 or earlier?
Mikel over 11 years

@user31522 Please update your question, which says you're using ksh.
user31522 over 11 years

OMG .... getting No Match ./test3 jboss5.0.3 No match ./test3 5.0.3 No match
user31522 over 11 years

Hi Mike ...yeah may be =~ is not with 2.*
Mikel over 11 years

Martin was guessing that you didn't want to allow numbers at the end. Change the last + to a *. And please update your question with clear examples of inputs and corresponding expected output.
lmcanavals over 11 years

To match jboss5.0.3 you need to change to ^[a-zA-Z]*5\.0\.3[a-zA-Z]*$. Because the + at the end, expects at least 1 character after the 5.0.3
user31522 over 11 years

Awesome !!! Thanks so much Mike and Marting .... it is working now after changing + to a... Thanks so much again for the help!!!
user31522 over 11 years

Hey Martin/Mike, I've updated my question. I believe it si little clear now. My apologies for the inconvenience caused. Thanks so much!