Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Very Basic Question regarding "while" loop

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Very Basic Question regarding "while" loop
# 15  
Old 05-22-2010
Yea, but afaik that would not react to any file modification (emptying, adding stuff, removing stuff), hence the checking for size.
On the other hand my approach would not react if the file gets deleted/removed Smilie
Last edited by pseudocoder; 05-22-2010 at 11:41 AM..
# 16  
Old 05-22-2010
Quote:
Originally Posted by pseudocoder
Yea, but afaik that would not react to any file modification (emptying, adding stuff, removing stuff), hence the checking for size.
On the other hand my approach would not react if the file gets deleted/removed Smilie
Well then lets add both the approaches.

Quote:
Slow and Steady Wins the RACE
Smilie
# 17  
Old 05-22-2010
What if the file somefile.txt is replaced with an empty somefile.txt ? At that time still there will be an entry in the inode table for this file. Right ?
# 18  
Old 05-22-2010
Interesting, until now I always thought that the file operator "-e" checks for existence of a file by file name, but it seems it also takes the inode number into account.

angshuman_ag,
there is always an inode number for every file. In the case that an existing file somefile.txt gets replaced with an empty somefile.txt, it's inode number will also be replaced with the inode number of the empty somefile.txt.
I've already checked that and the if statement (with file operator -e) immediately took effect when the existing somefile.txt got replaced by an empty somefile.txt, namely the while loop stopped the processing.
# 19  
Old 05-22-2010
Hi,

Quote:
Interesting, until now I always thought that the file operator "-e" checks for existence of a file by file name, but it seems it also takes the inode number into account.
Unix recognises files only by inode numbers. Thats the only reason that a file can have more than one names(hardlinks) but a unique inode number.

So once a file is removed and re-created by the same name, it has a different inode number and so [ -e file ] test will succeed in that regard.

Regards,
gaurav.
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

2. Shell Programming and Scripting

Failure: if grep "$Var" "$line" inside while read line loop

Hi everybody, I am new at Unix/Bourne shell scripting and with my youngest experiences, I will not become very old with it :o My code: #!/bin/sh set -e set -u export IFS= optl="Optl" LOCSTORCLI="/opt/lsi/storcli/storcli" ($LOCSTORCLI /c0 /vall show | grep RAID | cut -d " "... (5 Replies)
Discussion started by: Subsonic66
5 Replies

3. UNIX for Beginners Questions & Answers

Basic question on "echo"

what happens when I echo asterisk? Please don't hijack other peoples' thread; post our own new one as required by forum rules! (5 Replies)
Discussion started by: ithenr00
5 Replies

4. UNIX for Dummies Questions & Answers

Using "mailx" command to read "to" and "cc" email addreses from input file

How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

5. Shell Programming and Scripting

Question about the difference between "for" and "while" loop

dear all, i got some questions about for/while loop when working on redirect command output to for/while loop. take one for example : in for loop : allfiles=`find /var/log -maxdepth 1 -type f -mtime +5` index=1 for ((i=0; i<${#allfiles}; i++)); do echo "$index:${allfiles}" ... (2 Replies)
Discussion started by: tiger2000
2 Replies

6. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

7. UNIX for Advanced & Expert Users

A question/problem about oracle "tns listener" and "enterprise manager"

hi, I have a problem about the Oracle related components. I'm not able to find any answer yet, and waiting for your responses... Here is the configuration of my system: * an IBM P550 machine, * an AIX 5.3 running on it and * an oracle database, already installed on it. The problem (or... (1 Reply)
Discussion started by: talipk
1 Replies

8. UNIX and Linux Applications

A question/problem about oracle "tns listener" and "enterprise manager"

hi, I have * an IBM P550 machine, * an AIX 5.3 running on it and * an oracle database, already installed on it. The problem (or question of my own) is: Oracle tns listener, "CT_LISTENER", and the enterprise manager (EM) of the instance, which is uniq instance and called... (0 Replies)
Discussion started by: talipk
0 Replies

9. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies
Login or Register to Ask a Question