Difference between revisions of "$IFS"

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(Created page with '* The IFS is a special shell variable. * You can change the value of IFS as per your requirments. * The '''Internal Field Separator''' (IFS) that is used for word splitting after…')
 
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* The default value is '''<space><tab><newline>'''. You can print it with the following command:
 
* The default value is '''<space><tab><newline>'''. You can print it with the following command:
 
<source lang="bash">cat -etv <<<"$IFS"</source>
 
<source lang="bash">cat -etv <<<"$IFS"</source>
 +
*  IFS variable is commonly used with read command, parameter expansions and command substitution.
 +
 
From the bash man page:
 
From the bash man page:
 
<blockquote>
 
<blockquote>
 
The shell treats each character of IFS as a delimiter, and splits the results of the other expansions into words on these characters.  If IFS is unset, or its value is exactly <space><tab><newline>, the default, then sequences of <space>, <tab>, and <newline> at the beginning and end of the results of the previous expansions are ignored, and any sequence of IFS characters not at the beginning or end serves to delimit  words.  If IFS has a value other than the default, then sequences of the whitespace characters space and tab are ignored at the beginning and end of the word, as long as the whitespace character is in the value of IFS (an IFS whitespace character).  Any character in IFS that is  not  IFS  whitespace,  along with  any  adjacent  IFS whitespace characters, delimits a field. A sequence of IFS whitespace characters is also treated as a delimiter.  If the value of IFS is null, no word splitting occurs.
 
The shell treats each character of IFS as a delimiter, and splits the results of the other expansions into words on these characters.  If IFS is unset, or its value is exactly <space><tab><newline>, the default, then sequences of <space>, <tab>, and <newline> at the beginning and end of the results of the previous expansions are ignored, and any sequence of IFS characters not at the beginning or end serves to delimit  words.  If IFS has a value other than the default, then sequences of the whitespace characters space and tab are ignored at the beginning and end of the word, as long as the whitespace character is in the value of IFS (an IFS whitespace character).  Any character in IFS that is  not  IFS  whitespace,  along with  any  adjacent  IFS whitespace characters, delimits a field. A sequence of IFS whitespace characters is also treated as a delimiter.  If the value of IFS is null, no word splitting occurs.
 
</blockquote>
 
</blockquote>

Revision as of 11:01, 9 March 2010

  • The IFS is a special shell variable.
  • You can change the value of IFS as per your requirments.
  • The Internal Field Separator (IFS) that is used for word splitting after expansion and to split lines into words with the read builtin command.
  • The default value is <space><tab><newline>. You can print it with the following command:
cat -etv <<<"$IFS"
  • IFS variable is commonly used with read command, parameter expansions and command substitution.

From the bash man page:

The shell treats each character of IFS as a delimiter, and splits the results of the other expansions into words on these characters. If IFS is unset, or its value is exactly <space><tab><newline>, the default, then sequences of <space>, <tab>, and <newline> at the beginning and end of the results of the previous expansions are ignored, and any sequence of IFS characters not at the beginning or end serves to delimit words. If IFS has a value other than the default, then sequences of the whitespace characters space and tab are ignored at the beginning and end of the word, as long as the whitespace character is in the value of IFS (an IFS whitespace character). Any character in IFS that is not IFS whitespace, along with any adjacent IFS whitespace characters, delimits a field. A sequence of IFS whitespace characters is also treated as a delimiter. If the value of IFS is null, no word splitting occurs.