Sponsored Content
Top Forums Shell Programming and Scripting Script to change first line of files in directory Post 302653597 by alister on Saturday 9th of June 2012 02:36:04 PM
Old 06-09-2012
Quote:
Originally Posted by agama
I would suggest one small change: add some error checking to the cd command. If the user mistypes the path, it will work on all files in the current directory which is probably not what is intended.

Code:
if ! cd "${1:-no-such-directory}"     # also quote on the off chance that something in the path has spaces
then
   echo "abort: could not switch to '$1' or parameter was missing"
   exit 1
fi


Bah! Where's the fun in that? Smilie

You are correct, of course. Better safe than sorry, especially when the damage can be so severe.

However, I think the parameter expansion, cd "${1:-no-such-directory}" is misguided. As unlikely as it may be to exist, no-such-directory is a valid directory name. In my opinion, it's a bad idea to replace an absent or empty parameter with anything, in this instance.

Regards,
Alister

---------- Post updated at 02:36 PM ---------- Previous update was at 02:25 PM ----------

It's much safer and appropriate for that replacement to occur when $1 is referenced in the echo statement.

Regards,
Alister
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

How do I change ownership of a directory and all of it's files.

How do I change ownership of a directory and all of it's files without changing permissions? (1 Reply)
Discussion started by: mborin
1 Replies

2. Shell Programming and Scripting

Change Directory via a script?

I would like to have a script that would change my current working directory. However, any time I execute a 'cd' command in a script, it holds only for the life of that script -- the working directory on exit is the same as when the script was initiated. Is it possible to have the script return... (3 Replies)
Discussion started by: George Borrmann
3 Replies

3. Shell Programming and Scripting

Change of directory thru script

:confused: Hi All, This script is not working. I want to change the directory as per users selection in current shell. Looks like it is spawning sub-shell internally. I have used . changedir.sh source changedir.sh ./changedire.sh But did not work. Currently shell directory remain the... (4 Replies)
Discussion started by: shiningram
4 Replies

4. Shell Programming and Scripting

change directory using shell script

How do u change ur directory using a shell script?? (0 Replies)
Discussion started by: laxmi
0 Replies

5. Linux

Change directory in a shell script

How do u change ur directory using a shell script?? (12 Replies)
Discussion started by: laxmi
12 Replies

6. Shell Programming and Scripting

Script to change file contents line by line

Hi, I'm struggling to write a script to do the following, -will go through each line in the file -in a specific character positions, changes the value to a new value -These character positions are fixed througout the file ----------------------- e.g.: file1.sh will have the following 3... (4 Replies)
Discussion started by: vini99
4 Replies

7. Shell Programming and Scripting

directory change in shell script

Hi, I am trying to change the directory in my script, & want to check if the directory is present or not . Ex: cd /home/xyz/temp/logs if the logs directory is not present i want to show the error in script instead of shell script error. Can anybody please help me on the same Thx in... (2 Replies)
Discussion started by: vls1210
2 Replies

8. Shell Programming and Scripting

How to change a directory in shell script?

HI, I need to change the working directory by using the shell script /Export/home/user_name I have to go one step back like /Export/home Please help on this.:confused: (3 Replies)
Discussion started by: thelakbe
3 Replies

9. Shell Programming and Scripting

Apply 'awk' to all files in a directory or individual files from a command line

Hi All, I am using the awk command to replace ',' by '\t' (tabs) in a csv file. I would like to apply this to all .csv files in a directory and create .txt files with the tabs. How would I do this in a script? I have the following script called "csvtabs": awk 'BEGIN { FS... (4 Replies)
Discussion started by: ScKaSx
4 Replies

10. Shell Programming and Scripting

Change ? char from files and directory

Hello, I must change files and dirs name which contains che "?" char, I try this: rename 's/?/-/' *.* nothing, what's the problem? thanks (14 Replies)
Discussion started by: ionral
14 Replies
uudemon(4)						     Kernel Interfaces Manual							uudemon(4)

NAME
uudemon.admin, uudemon.cleanu, uudemon.hour, uudemon.poll - Administrative shell scripts for polling remote systems, cleaning up spool directories, reporting status to the system administrator, and routine invocations of the uuxqt and uusched daemons SYNOPSIS
These shell scripts reside in the following directory: /usr/lib/uucp DESCRIPTION
All the scripts can be run from the command line or can be run automatically by the cron daemon. To automatically run the scripts, remove the comment character (#) from the beginning of the relevant line in the /var/spool/cron/crontabs/uucp file. This script reports status to the system administrator. It issues the uustat command to find out the status of uucp jobs. It mails the results to the uucp login ID. The script may be modified to send mail to any login ID such as the uucp administrative login ID (uucpa) or root. This script cleans up the /var/spool/uucp and /var/spool/uucppublic directories by running the uucleanup command. The uucleanup com- mand is run with the following parameters: -C7, -D7, X2, -o2, -W1. This script runs the uusched and uuxqt daemons in the background. This script polls the systems listed in the /usr/lib/uucp/Poll file. The uudemon.poll script should be scheduled before the uudemon.hour script. This allows uudemon.poll to create any command files before cron runs the uudemon.hour script. FILES
Contains the uudemon.admin, uudemon.cleanu, uudemon.hour and uudemon.poll files. Contains the uucp file. RELATED INFORMATION
Commands: cron(8), uucleanup(8), uusched(8), uuxqt(1) Files: /usr/lib/uucp delim off uudemon(4)
All times are GMT -4. The time now is 07:55 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy