I'm trying to figure out how to disable the echo flag in C. I want to do this because I am coding a C program that must ask for a users password, so I would like to disable Echo, let...

Continue reading about How can I read a password without echoing it in C?

On page 329 (Hour 16) of your book Teach Yourself Unix in 24 Hours is the example: value=3 ; string="my horse Horace"test $value test `wc –l filename` -ge 10000 If I try this with this code: #!/bin/sh/value=3;string="my horse Horace"test $value...

Continue reading about What does the $( ) notation mean in a Bash script?

I'm studying Unix, and i need help writing a script. The script requires that it outputs the number of months and years from January 2007 to December 2017 inclusive that have a Friday the thirteenth....

Continue reading about How many Friday the 13ths are there in a given year?

I've been experimenting with mencoder to convert my AVI movies into a format that I can download onto my cellphone and finally found a site where they explain the various parameters needed for the mencoder program to get it to...

Continue reading about How do I turn a command line into a shell script?

I run a fairly busy Web site with a variety of different image directories. The problem is, Apache shows directories in a fairly rudimentary way which makes it quite difficult to find a specific image if I don't remember its...

Continue reading about Can I create an Apache image directory browser script?

Just picked up your book Wicked Cool Shell Scripts and already have one quick question: While working on the startup scripts, I would like to place log timers at certain portions of scripts. Is it possible to log point A...

Continue reading about How can I time portions of a Linux shell script?

This might sound like some wild conspiracy theory, but I'm looking at my music collection and it sure seems like most of them have exactly 12 tracks, no more, no less. Is there some marketing reason this would be the...

Continue reading about Do most music CDs have 12 tracks?

I need to rename thousands of files in MacOS, buried in subdirectories, changing " " to "_". I've found a ton of scripts using Google that purport to do this, but none of them actually work right. Can you please...

Continue reading about Script to rename thousands of files and directories?

I have a file containing lines of data that are amounts padded with leading zeros, similar to the snip below.   0000000004   0000000016   0000000012   0000000008 Using a shell script, how can I add up a column of...

Continue reading about How do I strip leading zeroes for math in a shell script?

i am having difficulties writing a script to back up files which have need modified during the month specified in the option. The command is: -b username yyyymm so if i say 200504. i will have to back up all...

Continue reading about How do I identify files changed during a specific month?

I'm a bit baffled. I'm trying to compare string variables in a shell script to figure out if one value is lexically less (that is, would appear earlier in the dictionary) than another, but it doesn't seem to work at...

Continue reading about String comparisons don't work in shell scripts?

I need to run a Unix application if a different application is running, from within a shell script. How do I do this?...

Continue reading about How can I run an app if another app is running?