Hello!
I want to read a file line by line and have each line in a variable. I have found the following code.
I don't understand the use of exec and its arguments, though having read some man pages and other forums. Could someone please enlighten me?
An example along with the explanation would be welcomed.
Hi,
Could you please explain me the below statement -- phrase wise.
sed -e :a -e '$q;N;'$cnt',$D;ba' abc.txt > xyz.txt
if suppose $cnt contains value: 10
it copies last 9 lines of abc.txt to xyz.txt
why it is copying last 9 rather than 10.
and also what is ba and $D over there in... (4 Replies)
Its great someone provided this script that strips out a filename and extension but can someone explain how each line works?
file1='Jane Mid Doe.txt'
newfile='Jane.txt'
1) ext=${file1##*.}
2) filename=${file%%.???}
3) set -- $filename
4) newfile="1.$extension" (1 Reply)
hi this is the output of showrev command from my sun blade 150 machine.
bash-3.00# showrev
Hostname: u15_9
Hostid: 83685284
Release: 5.10
Kernel architecture: sun4u
Application architecture: sparc
Hardware provider: Sun_Microsystems
Domain: sun.com
Kernel version: SunOS 5.10... (1 Reply)
Hi all,
I'm very new to UNIX. I have got a coding, where i dont understand the below part. Could someone please explain it in detail?
awk 'NR > 1; NR == 1 { S = $0 } END { print S }' $textfile.bak > $textfile
could someone explain what
awk 'NR > 1; NR == 1 { S = $0 } END { print S }'
... (1 Reply)
Could someone explain why Python 3.1 errors out below? Do I need an additional module that's not required in 3.2 perhaps? I need to use 3.1 as it's the version available on a server I am using.
Python 3.2.1rc1 (default, May 18 2011, 11:01:17)
on linux2
Type "help", "copyright", "credits"... (0 Replies)
I have the following bash script lines in a file named test.sh.
#!/bin/bash
#
# Write Date to cron.log
#
echo "Begin SSI Load $(date +%d%b%y_%T)"
#
# Get the latest rates file for processing.
#
d=$(ls -tr /rms/data/ssi | grep -v "processed" | tail -n 1)
filename=$d
export filename... (3 Replies)
grep -E '^(++){5}5000' <file_name>
this command searches value 5000 in only 6th column from provided file where pipe ( | )is delimiter which separate columns... can some one plz explain me what '^(++){5}5000' actually does..? :confused: (1 Reply)
I had gone through..google search.....and unix user post.......where I found so many ways of accessing files..... suppose if I am having 4 files, each file is having 3 columns, and I want to use each field of each column, then how can I use it.. how can I create array for each file's each column,... (8 Replies)
Hey Friends, its me again! :o
I was asked to create a script that would go into our backup directories and delete/purge anything in the directory after a certain amount of days, normally I would be able to write something up that goes to the directory finds it and deletes it.
cd... (12 Replies)
#!/bin/bash
n=$l; typeset -a v
x=$(< input.dat)
check(){
if; then
sed 's/Test/Proc/g' file.sh >fl.sh
else
exit 13
fi
}
check $n
while ; do
x=`expr $x -l`
v=$x
done
less fi.sh l>/dev/null&& echo yes || exit 1
echo v= ${v
}
exit 0
I have file.sh and input.dat in the current... (3 Replies)
Discussion started by: bananasprite
3 Replies
LEARN ABOUT HPUX
source
exec(1) User Commands exec(1)NAME
exec, eval, source - shell built-in functions to execute other commands
SYNOPSIS
sh
exec [argument...]
eval [argument...]
csh
exec command
eval argument...
source [-h] name
ksh
*exec [arg...]
*eval [arg...]
DESCRIPTION
sh
The exec command specified by the arguments is executed in place of this shell without creating a new process. Input/output arguments may
appear and, if no other arguments are given, cause the shell input/output to be modified.
The arguments to the eval built-in are read as input to the shell and the resulting command(s) executed.
csh
exec executes command in place of the current shell, which terminates.
eval reads its arguments as input to the shell and executes the resulting command(s). This is usually used to execute commands generated as
the result of command or variable substitution.
source reads commands from name. source commands may be nested, but if they are nested too deeply the shell may run out of file descrip-
tors. An error in a sourced file at any level terminates all nested source commands.
-h Place commands from the file name on the history list without executing them.
ksh
With the exec built-in, if arg is given, the command specified by the arguments is executed in place of this shell without creating a new
process. Input/output arguments may appear and affect the current process. If no arguments are given the effect of this command is to mod-
ify file descriptors as prescribed by the input/output redirection list. In this case, any file descriptor numbers greater than 2 that are
opened with this mechanism are closed when invoking another program.
The arguments to eval are read as input to the shell and the resulting command(s) executed.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
EXIT STATUS
For ksh:
If command is not found, the exit status is 127. If command is found, but is not an executable utility, the exit status is 126. If a redi-
rection error occurs, the shell exits with a value in the range 1-125. Otherwise, exec returns a zero exit status.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), ksh(1), sh(1), attributes(5)SunOS 5.10 17 Jul 2002 exec(1)