To read the file in '$1", you can simply cat "$1" but for the next requirement, write something with a loop that says:
Code:
#!/bin/bash
while read the_line; do
echo "$the_line"
done < "$1"
exit 0
From the example you wrote, you need to read every other line
Code:
#!/bin/bash
while read the_line; do
((i++%2)) && { echo "$the_line";}
done < "$1"
exit 0
i is a variable that's incremented (i++) on every line read. i%2 returns 1 or 0, depending i is odd or even, basically, it returns 0 when i is 2; 4; 6; ...
And in sh/bash and many others scripting languages; zero means no errors.
No Errors: execute what's after the &&, so echo "$the_line"
hi, first congratulations on the nice forum!
Can anybody write script, which can make copy of some or all files of the current directory in new directory (called "backups", which must be made in the current directory, if it's not already exist). And bring out a massage (report) with the count... (7 Replies)
Hi,
root@server] df -h
121G 14G 101G 12% /home
147G 126G 14G 91% /backup
We having our site files and images are storing in
/backup/home/user/files/ through symbolic link created in /home directory pointing in /backup directory as following.
root@server] cd /home... (1 Reply)
I am very new to Linux/Unix. Kindly assist the following:
I wish to write a bash shell script called how_many_to_go that calculates and prints the number of days, hours, minutes and/or seconds until the end of the current month (based on the output of the date command).
Do ... (2 Replies)
Hi All
I am a new in scripting language and I would like help for you guys
I would like to create a file named constant.h and search into all files *.m in specific directory for a reg-exp @"LBL_]+" exp: @"LBL_75847" , and write those matchs to constant.h if there are not written (no... (15 Replies)
i'm trying to write a bash script that that will automatically extract zip files after the download.
i writed this script
#!/bin/bash
wget -c https://github.com/RonGokhle/kernel-downloader/zipball/master
CURRENDIR=/home/kernel-downloader
cd $CURRENDIR
rm $CURRENDIR/zipfiles 2>/dev/null
... (2 Replies)
Hi All,
I am unable to write the script for the below requirement.
Requirement:
Main table dir_ancillary table contain three column "dir_ancillary.table_name"," dir_ancillary.text_file_name ", "dir_ancillary.Include" .
This dir_ancillary contain undefined tables in the column... (2 Replies)
Hi Team
I am trying to put together a nice small script to mount my lvm snapshot
Here are my objectives
1 Check whether snapshot is currently mounted. If so echo umount snapshot and exit from the script.
2 If it's not mounting, check whether the mount point exist, If so, create lvm... (0 Replies)
Hello experts, I need help writing individual files from a data matrix, with each new file being written every time there is a blank line:
From this
cat file.txt
col1 col2 col3
6661 7771 8881
6661 7771 8881
6661 7771 8881
col1 col2 col3
3451 2221 1221... (6 Replies)
Hello guys, I need some help. I am new in bash and I don't know how to automate the following script.
head -2 out1 > 1.fasta
sed ‘1,2 d' out1 > out2
rm out1
head -2 out2 > 2.fasta
sed ‘1,2 d' out2 > out1
rm out2
head -2 out2 > 3.fasta
sed '1,2 d' out2 > out1
rm out2
.......... (3 Replies)
How would I write a value to a physical memory address?
I was able to read a physical memory address (for example, 0x400) using this line:
dd if=/dev/mem count=4 bs=1 skip=$(( 0x400 ))
But I get an error:
dd: 'standard input': cannot skip to specified offset
when I try to write using... (1 Reply)
Discussion started by: rabrandt
1 Replies
LEARN ABOUT LINUX
rbash
RBASH(1) General Commands Manual RBASH(1)NAME
rbash - restricted bash, see bash(1)RESTRICTED SHELL
If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is
used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the follow-
ing are disallowed or not performed:
o changing directories with cd
o setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV
o specifying command names containing /
o specifying a file name containing a / as an argument to the . builtin command
o specifying a filename containing a slash as an argument to the -p option to the hash builtin command
o importing function definitions from the shell environment at startup
o parsing the value of SHELLOPTS from the shell environment at startup
o redirecting output using the >, >|, <>, >&, &>, and >> redirection operators
o using the exec builtin command to replace the shell with another command
o adding or deleting builtin commands with the -f and -d options to the enable builtin command
o using the enable builtin command to enable disabled shell builtins
o specifying the -p option to the command builtin command
o turning off restricted mode with set +r or set +o restricted.
These restrictions are enforced after any startup files are read.
When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script.
SEE ALSO bash(1)GNU Bash-4.0 2004 Apr 20 RBASH(1)
06-06-2011
