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bash with: if, elif & regex not working

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Top Forums Shell Programming and Scripting bash with: if, elif & regex not working
# 1  
Old 01-25-2010
bash with: if, elif & regex not working
Why is only hello3 being printed? There must be some kind of syntax problem because the file list definitely includes all the file extensions line by line.

PHP Code:
#!/bin/bash

find '/home/myuser/folder/' -name '*.c' -type f | while read F
do
    if [[ "$F" == '*.txt.c' ]] # if the file name ends in .txt.c
    then
        echo hello1
    elif [[ "$F" == '*.c' && "$F" != '*.txt.c' && "$F" != '*.xml.c' ]] # if the file name does end in .c but not in txt.c nor .xml.c
    then
        echo hello2
    else # is this else necessary ?
        echo hello3
    fi
done 
# 2  
Old 01-25-2010
Try:
Code:
    if [[ $F == *.txt.c ]] # if the file name ends in .txt.c
    then
        echo hello1
    elif [[ $F == *.c && $F != *.txt.c && $F != *.xml.c ]] # if the file name ...
    then

# 3  
Old 01-25-2010
If I was doing the test you are trying to do with:
Quote:
if [[ "$F" == '*.txt.c' ]]
which is testing for a file literally called *.txt.c, if you changed the test to == "*.txt.c" then you would be comparing $F with a list of files in the pwd named <anything>.txt.c.

I would do it as:
Code:
if [[ -n "`echo ${F} | grep '\.txt\.c$'`" ]]

But then I tend to write Bourne shell with a few Korn shell enhancements when necessary.[COLOR="#738fbf"]
Last edited by TonyFullerMalv; 01-25-2010 at 07:22 PM.. Reason: Corrected code now edit button has reappeared!
# 4  
Old 01-25-2010
Inside [[ ]] word splitting and wildcard expansion are not performed. So if you use == "*.txt.c" you are still comparing to a literal asterisk. Therefore you need to drop the "" as well in the case of pattern. "" are used for literal string matches. So you can use for example:
Code:
[[ $var == pattern ]] || [[ $var == "string" ]]

# 5  
Old 01-25-2010
OK, I just realized that my system uses dash (not bash). So it works with bash but in dash it ouputs these errors. Any idea why? I really want to stick with dash syntax and not use programs like grep etc. when not strictly necessary.

This works in bash but not in dash:
PHP Code:
#!/bin/dash

find '/home/myuser/folder/' -name '*.c' -type f | while read F
do
    if [[ $F == *.css.c ]]
    then
        echo hello1
    elif [[ $F == *.c && $F != *.txt.c && $F != *.xml.c ]]
        echo hello2
    else
        echo hello3
    fi
done 

Quote:
./shell.sh: 14: [[: not found
./shell.sh: 14: [[: not found
hello3
./shell.sh: 14: [[: not found
./shell.sh: 14: [[: not found
hello3
# 6  
Old 01-25-2010
Bourne shell only accepts:
Code:
if [ test ]

Perhaps dash is the same?
# 7  
Old 01-25-2010
Dash is posix compliant without all the additional bells and whistles that bash provides, so the [[ ... ]] is not available. You can use the [ ... ] construct, but not with patterns. So I think you should use a case statement:

Code:
find '/home/myuser/folder/' -name '*.c' -type f |
while read F
do
  case $F in
    *.css.c)         echo hello1 ;;
    *.txt.c|*.xml.c) echo hello3 ;;
    *.c)             echo hallo2 ;;
    *)               echo hello3 ;;
  esac
done

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