Sponsored Content
Full Discussion: File is not empty?
Top Forums Shell Programming and Scripting File is not empty? Post 19075 by Kelam_Magnus on Friday 5th of April 2002 11:39:00 AM
Old 04-05-2002
The test command is your best bet.

Look at the bottom -z is for zero test and -n is for non-zero test.


man test
test(1) test(1)
NAME
test - condition evaluation command
SYNOPSIS
test expr
[ expr ]
DESCRIPTION
The test command evaluates the expression expr and, if its value is
True, returns a zero (true) exit status; otherwise, a nonzero (false)
exit status is returned. test also returns a nonzero exit status if
there are no arguments. The following primitives are used to
construct expr:
-r file True if file exists and is readable.
-w file True if file exists and is writable.
-x file True if file exists and is executable.
-f file True if file exists and is a regular file.
-d file True if file exists and is a directory.
-c file True if file exists and is a character special
file.
-b file True if file exists and is a block special file.
-p file True if file exists and is a named pipe (fifo).
-u file True if file exists and its set-user-ID bit is
set.
-g file True if file exists and its set-group-ID bit is
set.

-k file True if file exists and its sticky bit is set.

-s file True if file exists and has a size greater than
zero.

-h file True if file exists and is a symbolic link.

-t [fildes] True if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device.

-z s1 True if the length of string s1 is zero.


-n s1 True if the length of the string s1 is non-zero.
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

empty file in hp-ux

Hi, I need your help. How can I create an empty filename with a specific size, in hp-ux? Regards, Mizi (2 Replies)
Discussion started by: Mizi
2 Replies

2. Shell Programming and Scripting

How to empty a file(already created)

What is the command to empty an already existing file. please provide me.i used Touch cmd to empty the file.but it changing the time only. (4 Replies)
Discussion started by: laknar
4 Replies

3. UNIX for Dummies Questions & Answers

how to find empty folders without using -empty

hi all: my solaris FIND does not support find myFolder -type d -empty how can i find the empty folders? thanks! (7 Replies)
Discussion started by: lasse
7 Replies

4. UNIX for Dummies Questions & Answers

Trying to empty file using > but the file size increasing when next append

AIX 5.3 / KSH I have a Java application which creates a log file a.log. I have a KSH script which does the following action cp a.log /directory2/b.log > a.log After this the file size goes to 0 as per "ls -l" Then next time when the application writes into this file, the file size... (4 Replies)
Discussion started by: firdousamir
4 Replies

5. Shell Programming and Scripting

how to see if the file is empty or not?

hi how can I determine, if a file is empty or not?I am using read line clause. The script should be like: while read line do if(file is empty) then; ...... done < $blacklist (1 Reply)
Discussion started by: tjay83
1 Replies

6. UNIX for Dummies Questions & Answers

Getting same exit status for empty and non empty file

Hi All, I am checking for a empty input file to do some further action , but I am getting exit status 0 in both the cases , for empty and non empty file both. The value of $? is coming 0 in if part also and else part too. #!/bin/ksh if ]; then echo "data" # exit 0 echo "$?" else... (4 Replies)
Discussion started by: mavesum
4 Replies

7. Shell Programming and Scripting

while file is empty

how can i use while loop ? while file is empty do.... if not empty do ..... in bash (1 Reply)
Discussion started by: Trump
1 Replies

8. Shell Programming and Scripting

Empty out the file

Hi All, I have a piece of perl code in which I DON'T want to delete a file rather empty out the contents, here is the code - if ( unlink("$opt_b") == 1 ) { print_log( "$opt_b deleted", 1 ); }else { print_log( "Could not delete $opt_b:$!", 1 ); ... (5 Replies)
Discussion started by: jacki
5 Replies

9. Shell Programming and Scripting

if/else with an empty file...

Hi there, I'm just starting out with shell scripting and I'm trying to make a test where the script will basically run yum check-update to find out if the server has any available and if it does it e-mails me but if not it will just stop there. I have it working if there are actually... (7 Replies)
Discussion started by: Imnewtothis
7 Replies

10. Shell Programming and Scripting

awk to reformat output if input file is empty, but not if file has data in it

The below awk improved bu @MadeInGermany, works great as long as the input file has data in it in the below format: input chrX 25031028 25031925 chrX:25031028-25031925 ARX 631 18 chrX 25031028 25031925 chrX:25031028-25031925 ARX 632 14... (3 Replies)
Discussion started by: cmccabe
3 Replies
test(1sh5)																test(1sh5)

Name
       test - condition evaluation command

Syntax
       test expr
       [ expr ]

Description
       The  command  evaluates the expression expr.  If the value of expr is true, the command returns a zero exit status; otherwise, it returns a
       nonzero exit status.  The command also returns a nonzero exit status if no arguments are specified.  The following primitives are  used	to
       construct expr:

       -r file	      True if file exists and is readable.

       -w file	      True if file exists and is writable.

       -x file	      True if file exists and is executable.

       -f file	      True if file exists and is a regular file.

       -d file	      True if file exists and is a directory.

       -c file	      True if file exists and is a character special file.

       -b file	      True if file exists and is a block special file.

       -p file	      True if file exists and is a named pipe (fifo).

       -u file	      True if file exists and its set-user-ID bit is set.

       -g file	      True if file exists and its set-group-ID bit is set.

       -k file	      True if file exists and its sticky bit is set.

       -s file	      True if file exists and has a size greater than zero.

       -t [ fildes ]  True if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device.

       -z s1	      True if the length of string s1 is zero.

       -n s1	      True if the length of the string s1 is non-zero.

       s1 = s2	      True if strings s1 and s2 are identical.

       s1 != s2       True if strings s1 and s2 are not identical.

       s1	      True if s1 is not the null string.

       n1 -eq n2      True  if	the integers n1 and n2 are algebraically equal.  Any of the comparisons -ne, -gt, -ge, -lt, and -le may be used in
		      place of -eq.

       These primitives can be combined with the following operators:

       !	      unary negation operator.

       -a	      binary and operator.

       -o	      binary or operator (-a has higher precedence than -o).

       ( expr )       parentheses for grouping.

       Note that all the operators and flags are separate arguments to the command.  Note also that parentheses are meaningful to  the	Shell  and
       must  be  escaped.   In the form of the command that uses square brackets ([]), instead of the word test, the brackets must be delimited by
       blanks.

See Also
       find(1), sh5(1), test(1)

																	test(1sh5)
All times are GMT -4. The time now is 03:30 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy