Further to abubacker and for completeness.
We put $groupline in double quotes or we get a syntax error from the if statement if the line is blank.
As other posters note the "for" method loses the blank line completely when expanding the output from "cat" on the command line.
The "while read" construct is preferred because it can deal with any number of records whereas the "for" method could expand to a command line which fails because it is too long.
A version with "cat":
Last edited by methyl; 02-26-2010 at 07:57 AM..
Reason: Layout
Hello,
So I sorted my file as I was supposed to:
sort -n -r -k 2 -k 1 file1 | uniq > file2
and when I wrote
> cat file2
in the command line, I got what I was expecting, but in the script itself
...
sort -n -r -k 2 -k 1 averages | uniq > temp
cat file2
It wrote a whole... (21 Replies)
The following grep command grep -v "^$" filename > newfilename does not populate the new file with any data. I see it search the entire input file but the output file never gets filled. Is this not the correct command for what Im looking to do? (2 Replies)
Hi,
Consider a file named "testfile"
The contents of file are as below
first line added for test
second line added for test
third line added for test
fourth line added for test
fifth line added for test (5 Replies)
Hello All,
I have a bash script and in it at some point I call an Expect Script that does some stuff and saves its
output in a ".txt" file.
Example "/path/to/my/file/Expect_Output.txt" file: notice the 2nd line is empty in the file...
Data for Host-1 (192.168.1.110)
Checking the... (2 Replies)
I have a file say ADCD which is like following-->
Please consider 'z' as space
#cat ADCD
<!--Yzzz|z-->
<!--Nzzzzz-->
Now I want to store the content of this file to a variable say VAR like this-->
#VAR=`cat ADCD`
#echo $VAR
<!--Yz|z--> <!--Nz-->
Now I don' t want the variable... (2 Replies)
I use the cat command to concatenate text files, but one of the rows I was expecting doesn't display in the output file. Is there a verbose mode\logging mechanism for the cat command to help me investigate where the lines I was expecting are going??
cat 7760-001_1_*_06_*.txt | grep -v... (1 Reply)
Hi Team,
The content of the file is as follows.
asdf
234
asdf
asdf
dsfg
gh
67
78
The file is in DOS format (not in Unix Format). The file is transferred to Unix. I need a unix command to check the number of blank lines in a input (comming from Windows). If it is greater than... (4 Replies)
plz help me to figure it out
how i remove empty or blank files using cat command.
i will be very thankful if u send me this answer...
thanks (3 Replies)
Hi All
Need Help
I have a file with the below format (ABC.TXT) :
®¿¿ABCDHEJJSJJ|XCBJSKK01|M|7348974982790
HDFLJDKJSKJ|KJALKSD02|M|7378439274898
KJHSAJKHHJJ|LJDSAJKK03|F|9898982039999
(cont......)
I need to write a script where it will check for : blank lines (between rows,before... (6 Replies)
Discussion started by: chatwithsaurav
6 Replies
LEARN ABOUT OSX
cat
CAT(1) BSD General Commands Manual CAT(1)NAME
cat -- concatenate and print files
SYNOPSIS
cat [-benstuv] [file ...]
DESCRIPTION
The cat utility reads files sequentially, writing them to the standard output. The file operands are processed in command-line order. If
file is a single dash ('-') or absent, cat reads from the standard input. If file is a UNIX domain socket, cat connects to it and then reads
it until EOF. This complements the UNIX domain binding capability available in inetd(8).
The options are as follows:
-b Number the non-blank output lines, starting at 1.
-e Display non-printing characters (see the -v option), and display a dollar sign ('$') at the end of each line.
-n Number the output lines, starting at 1.
-s Squeeze multiple adjacent empty lines, causing the output to be single spaced.
-t Display non-printing characters (see the -v option), and display tab characters as '^I'.
-u Disable output buffering.
-v Display non-printing characters so they are visible. Control characters print as '^X' for control-X; the delete character (octal
0177) prints as '^?'. Non-ASCII characters (with the high bit set) are printed as 'M-' (for meta) followed by the character for the
low 7 bits.
EXIT STATUS
The cat utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
The command:
cat file1
will print the contents of file1 to the standard output.
The command:
cat file1 file2 > file3
will sequentially print the contents of file1 and file2 to the file file3, truncating file3 if it already exists. See the manual page for
your shell (i.e., sh(1)) for more information on redirection.
The command:
cat file1 - file2 - file3
will print the contents of file1, print data it receives from the standard input until it receives an EOF ('^D') character, print the con-
tents of file2, read and output contents of the standard input again, then finally output the contents of file3. Note that if the standard
input referred to a file, the second dash on the command-line would have no effect, since the entire contents of the file would have already
been read and printed by cat when it encountered the first '-' operand.
SEE ALSO head(1), more(1), pr(1), sh(1), tail(1), vis(1), zcat(1), setbuf(3)
Rob Pike, "UNIX Style, or cat -v Considered Harmful", USENIX Summer Conference Proceedings, 1983.
STANDARDS
The cat utility is compliant with the IEEE Std 1003.2-1992 (``POSIX.2'') specification.
The flags [-benstv] are extensions to the specification.
HISTORY
A cat utility appeared in Version 1 AT&T UNIX. Dennis Ritchie designed and wrote the first man page. It appears to have been cat(1).
BUGS
Because of the shell language mechanism used to perform output redirection, the command ``cat file1 file2 > file1'' will cause the original
data in file1 to be destroyed!
The cat utility does not recognize multibyte characters when the -t or -v option is in effect.
BSD March 21, 2004 BSD