Diff for "BashFAQ/066"

Differences between revisions 4 and 12 (spanning 8 versions)

I want to check if [[ $var == foo || $var == bar || $var == more ]] without repeating $var n times.

The portable solution uses case:

   # Bourne
   case "$var" in
      foo|bar|more) ... ;;
   esac

In Bash and ksh, Extended globs can also do this within a [[ command:

   # bash/ksh -- ksh does not need the shopt
   shopt -s extglob
   if [[ $var = @(foo|bar|more) ]]; then
      ...
   fi

Alternatively, the "inarray" function could be used:

   # usage: inarray NEEDLE HAYSTACK ...
   # returns 0 if NEEDLE is in HAYSTACK, otherwise 1.
   inarray() {
     local n=$1 h
     shift

     for n; do
       [[ $n = "$h" ]] && return
     done
     return 1
   }

   if inarray $var foo bar more; then
     ...
   fi

CategoryShell

-  ⇤ ← Revision 4 as of 2007-05-24 15:23:46 → 
  Size: 813
  Editor: GreyCat
  Comment: a workaround
+   ← Revision 12 as of 2013-01-03 17:46:44 → ⇥
  Size: 838
  Editor: static-74-106-235-64
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-[[Anchor(faq66)]]
+<<Anchor(faq66)>>
 Line 3:
+The portable solution uses `case`:
-Line 4:
+Line 5:
-Here's a portable solution:
 Line 6:
-   case $var in
+   # Bourne
   case "$var" in
-Line 11:
+Line 12:
-And here's one that uses `=~` (which requires bash 3.0 or higher):
+In Bash and ksh, [[glob|Extended globs]] can also do this within a `[[` command:
-Line 13:
+Line 14:
-   regex='^(foo|bar|more)$'
   if [[ $var =~ $regex ]]; then
+   # bash/ksh -- ksh does not need the shopt
   shopt -s extglob
   if [[ $var = @(foo|bar|more) ]]; then
-Line 19:
+Line 21:
-This one '''only works in bash 3.1''', not in bash 3.2 (and is untested in 3.0):
+Alternatively, the "inarray" function could be used:
-Line 21:
+Line 23:
-   if [[ $var =~ '^(foo|bar|more)$' ]]; then
      ...
+   # usage: inarray NEEDLE HAYSTACK ...
   # returns 0 if NEEDLE is in HAYSTACK, otherwise 1.
   inarray() {
     local n=$1 h
     shift

     for n; do
       [[ $n = "$h" ]] && return
     done
     return 1
   }

   if inarray $var foo bar more; then
     ...
-Line 26:
+Line 40:
-Normally I would never advocate sticking code into a variable and attempting to use it -- lots of people have ''enormous'' trouble because they try to do that.  In the case of `=~`, though, it seems to be required.  Personally, I'd just stick with the `case`. --GreyCat
+----
CategoryShell