Tuesday, April 23, 2013

Commonly used Unix commands

Cut

Cut out selected fields of each line of a file.

Syntax

cut [-b] [-c] [-f] list [-n] [-d delim] [-s] [file]

-b list
   

The list following -b specifies byte positions (for instance, -b1-72 would pass the first 72 bytes of each line). When -b and -n are used together, list is adjusted so that no multi-byte character is split. If -b is used, the input line should contain 1023 bytes or less.

-c list
   

The list following -c specifies character positions (for instance, -c1-72 would pass the first 72 characters of each line).

-f list
   

The list following -f is a list of fields assumed to be separated in the file by a delimiter character (see -d ); for instance, -f1,7 copies the first and seventh field only. Lines with no field delimiters will be passed through intact (useful for table subheadings), unless -s is specified. If -f is used, the input line should contain 1023 characters or less.

list
   

A comma-separated or blank-character-separated list of integer field numbers (in increasing order), with optional - to indicate ranges (for instance, 1,4,7; 1-3,8; -5,10 (short for 1-5,10); or 3- (short for third through last field)).

-n
   

Do not split characters. When -b list and -n are used together, list is adjusted so that no multi-byte character is split.

-d delim
   

The character following -d is the field delimiter (-f option only). Default is tab. Space or other characters with special meaning to the shell must be quoted. delim can be a multi-byte character.

-s
   

Suppresses lines with no delimiter characters in case of -f option. Unless specified, lines with no delimiters will be passed through untouched.

file
   

A path name of an input file. If no file operands are specified, or if a file operand is -, the standard input will be used.

Examples

name=`who am i | cut -f1 -d' '`

Set name to current login name.



About cut


Cut out selected fields of each line of a file.


Syntax


cut [-b] [-c] [-f] list [-n] [-d delim] [-s] [file]


-b list The list following -b specifies byte positions (for instance, -b1-72 would pass the first 72

bytes of each line). When -b and -n are used together, list is adjusted so that no multi-byte character is split. If -b is used, the input line should contain 1023 bytes or less.

-c list The list following -c specifies character positions (for instance, -c1-72 would pass the first 72 characters of each line).

-f list The list following -f is a list of fields assumed to be separated in the file by a delimiter character (see -d ); for instance, -f1,7 copies the first and seventh field only. Lines with no field delimiters will be passed through intact (useful for table subheadings), unless -s is specified. If -f is used, the input line should contain 1023 characters or less.

list A comma-separated or blank-character-separated list of integer field numbers (in increasing order), with optional - to indicate ranges (for instance, 1,4,7; 1-3,8; -5,10 (short for 1-5,10); or 3- (short for third through last field)).

-n Do not split characters. When -b list and -n are used together, list is adjusted so that no multi-byte character is split.

-d delim The character following -d is the field delimiter (-f option only). Default is tab. Space or other characters with special meaning to the shell must be quoted. delim can be a multi-byte character.

-s Suppresses lines with no delimiter characters in case of -f option. Unless specified, lines with no delimiters will be passed through untouched.

file A path name of an input file. If no file operands are specified, or if a file operand is -, the standard input will be used.

Examples


name=`who am i | cut -f1 -d' '`


Set name to current login name.




WC-UNIX:

$ wc filename X Y Z filename
  • X – Number of lines
  • Y – Number of words
  • Z – Number of bytes
  • filename – name of the file
-l : Prints the number of lines in a file.
-w : prints the number of words in a file.
-c : Displays the count of bytes in a file.
-m : prints the count of characters from a file.
-L : prints only the length of the longest line in a file.

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