cat command (outputs files to the standard output)

Format

cat [-b] [-n] [-s] [-u] [path-name ...]

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Description

This command outputs one or more files to the standard output. If there are multiple files, they are concatenated and output.

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Arguments

-b

Specifies that all non-blank output lines are to be assigned line numbers.

-n

Specifies that all output lines are to be assigned line numbers beginning with 1. Each line number is displayed as six digits. If the number of lines is such that line numbers cannot be accommodated in six digits, the number of digits is increased as necessary. A tab is output after each line number.

-s

Specifies that multiple consecutive blank lines are to be compressed and output as a single blank line.

-u

In UNIX, specifies that output buffering is to be suppressed.

In Windows, this option is ignored.

path-name

Specify the path name of a file to be output. Multiple path names can be specified, in which case the specified files are concatenated and then output. If no path name is specified, or if - is specified as the path name, the input is read from the standard input.

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Return codes

Return code	Meaning
0	Normal termination
1 or greater	Error termination

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Notes

• A blank line is considered to be a line consisting of only a linefeed code [LF]. A line that includes [CR] + [LF] is not considered a blank line for the purposes of the -b and -s options. For this reason, files in Windows are normally not considered to include any blank lines.

• In Windows, input and output are performed in the binary mode for files and for the standard input and standard output. No conversion of linefeed codes is performed.

• If the standard output is a file and the specified path name indicates this file, the command outputs the following message and results in an error:

  cat: file-name: input file is output file

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Usage examples

These usage examples illustrate the results of executing the cat command on files abc.txt and abcdex.txt, whose contents are shown below. In the examples, represents a space and represents a tab character.

• abc.txt

  aaaaaaaaaaa
   
  bbbbbbbb
   
  
  cccccccccccccccc
   
                 
   
  
  dddddddddddd

• abcdex.txt

  aaaaaaaaaaa
  
  
  
  
  
  bbbbbbbb
   
   
   
   
   
  cccccccccccc
   
   
   
   
  dddddddddddd
   
   
   
   
   
   
   
  eeeeeeeeeeeeeeeee
           
           

The files listed above are used as input files in the following examples, which illustrate the results of executing the cat command.

• Specify the -b option to number non-blank output lines.

  $ cat -b abc.txt
       1aaaaaaaaaaa
   
       2bbbbbbbb
   
       3 
       4cccccccccccccccc
   
       5             
   
       6 
       7dddddddddddd

• Specify the -n option to number all output lines.

  $ cat -n abc.txt
       1aaaaaaaaaaa
       2
       3bbbbbbbb
       4
       5
       6cccccccccccccccc
       7
       8
       9
      10
      11dddddddddddd

• Specify the -s option to squeeze consecutive blank lines and output them as a single blank line.

  $ cat -s abcdex.txt
  aaaaaaaaaaa
  
  
  
  
  
  bbbbbbbb
   
  cccccccccccc
   
  dddddddddddd
   
  eeeeeeeeeeeeeeeee
           
           

• Display an option error message.

  This message might vary depending on the platform on which the command is executed. The following shows an example in Windows:

  C:\TEMP>%ADSH_OSCMD_DIR%\cat -w
  cat: illegal option -- w
  usage: cat [-bnsu] [file ...]

• Display an error message because a file does not exist:

  C:\TEMP>%ADSH_OSCMD_DIR%\cat file99
  cat: file99: No such file or directory

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