Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

awk's getline < "-" seems not work for pipe

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting awk's getline < "-" seems not work for pipe
# 15  
Old 04-09-2009
Thanks for you guys reply, it works!!Smilie

Then the question remained is how to make "exec 3>&0" work in shell script (maybe I need to start another thread for it)?
# 16  
Old 04-09-2009
Please post an example shell script that demonstrates that behavior.
# 17  
Old 04-09-2009
How to make exec 3>&0 in the shell script
So if I put exec 3>&0 in my shell script (call it aname ) like this

#!/usr/bin/sh
exec 3>&0
awk 'BEGIN {printf "Enter your name:" ; getline name < "/dev/fd/3"}{ print name, $3 }' $1

And running ls | aname won't get what I want

But if I type exec 3>&0 at shell prompt then run the script like,

#!/usr/bin/sh
awk 'BEGIN {printf "Enter your name:" ; getline name < "/dev/fd/3"}{ print name, $3 }' $1

ls | aname works.

So how to make exec 3>&0 (i.e. using exec to manipulation of file descriptors) works in shell script ?
# 18  
Old 04-09-2009
Inside your script you're making fd 3 a copy of the STDIN of the new shell started by the script which is not a terminal.
In this case it's just the data that passes through the pipe.
If you need to read from the controlling terminal, you should use /dev/tty as suggested.
Login or Register to Ask a Question

Previous Thread | Next Thread

8 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

awk script does not work when written as "one-liner"

In my quest to solve a bigger problem (See my previous post called "Create SQL DML insert statements from file using AWK or similar" - sorry, not allowed to post urls until I have > 5 posts) I'm trying to get my head round awk, but have some problem figuring out why the following script does work... (2 Replies)
Discussion started by: Yagi Uda
2 Replies

2. Shell Programming and Scripting

how to use "cut" or "awk" or "sed" to remove a string

logs: "/home/abc/public_html/index.php" "/home/abc/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" how to use "cut" or "awk" or "sed" to get the following result: abc abc xyz xyz xyz (8 Replies)
Discussion started by: timmywong
8 Replies

3. 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

4. Shell Programming and Scripting

Awk to Search and Replace inside the pipe "|"

Hi, Anyone can help me on how to replace the qoutes inside the pipe | in my Text File like belows; "AAAA"|"Test "1-A""|"Test AAAA"|"This is A" "BBBB"|"Test "1-B""|"Test BBBB"|"This is B" "CCCC"|"My Test C"|"Test "CCCC""|"This is C" The output I need like belows; "AAAA"|"Test 1-A"|"Test... (12 Replies)
Discussion started by: fspalero
12 Replies

5. Shell Programming and Scripting

acessing awk array element while getline < "file"

I am attempting to write a awk script that reads in a file after awk array elements are assigned and using those elements while reading in the new file. Does this make sense? /pattern/ {tst=$3} (( getline < "file" ) > 0 ) { x=x " "tst } When I print tst in the END statement it... (9 Replies)
Discussion started by: timj123
9 Replies

6. 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

7. Shell Programming and Scripting

awk: getline NOM < "-" script does not stop

Well , i have: $ cat example.dat 1 2 3 4 5 $ cat getline3.awk function getName (NOM) { printf "Enter a filename: " getline NOM < "-" # get response return NOM } BEGIN { printf ("\nREP: %s\n",getName(N)) } {print} This example works fine: (2 Replies)
Discussion started by: Klashxx
2 Replies

8. Linux

By angle-brackets/"pipe" button doesn't work?

How can I configure it? I have a swedish keyboard with swedish keyboard setting. Everything works perfectly (едц) except that button. What can be wrong? /Richard ++ NOTE: It seems like the computer notices the input but that the button isn't assigned to anything (the keyboard-cursor stops).... (1 Reply)
Discussion started by: riwa
1 Replies
Login or Register to Ask a Question