I want to replace a line with double quotes on OpenBox startup, like: with I use this command, but it does not work: It gives me this error: Answer The ampersand in the replacement string recalls the pattern in the search string. So you can just do this: Also, you can use single quotes on the outside, and double quotes
Tag: unix
Using the setuid bit in Linux
I have this C file: I compile it, set the UID and GID both to root and set the setuid bit, so that it looks like this: However when I call $ ./a.out I still get: What am I doing wrong? Answer The real user ID is still the user that called the program, but the effective user ID is
Print error for missing argument
I am trying to write a script which will check number of arguments for first and second number; if both variable entered, it will do the calculation; if one argument is missing, it will print error message. Here what I’ve done so far: I am always getting error message even though I enter both of the numbers. What am I
Save all data into variable tcl
I have a code which i want to use to open a log file, extract the contents and save it into a variable so i can extract the data from the variable in the future. How do i do that? So far the code saves only the last data of the log file into the variable. I think the while
tail the last modified file and monitor for new files in bash
I can tail -f the last modified file using ls –sort=time | head -1 | xargs tail -f but I’m looking for something that would continuously run the first part as well, i.e. if a new files is created while the tail command is running it switches to tailing the new file. I thought about using watch command but that
script for deleting queues using a certain prefix
i have a file named “Output_File.txt” containing a list of local queues and i want to write a script to delete those queues. what i wrote is: the problem is that the script does delete the queues but prints for every deleted queue the following output: how can i alter the code to delete the queues without printing the output
Recursively grep unique pattern in different files
Sorry title is not very clear. So let’s say I’m grepping recursively for urls like this: grep -ERo ‘(http|https)://[^/”]+’ /folder and in folder there are several files containing the same url. My goal is to output only once this url. I tried to pipe the grep to | uniq or sort -u but that doesn’t help example result: Answer If
mkdir makes wrong directory names when used with cut on *.tex files
When make directories for each file with certain extension: …everything works just fine. However if I do it for .tex files I get following results: I just wanted to clean my latex directory and I get weird directory names. Why is that and how to make it work? Answer It is error prone to use output from ls like this.
Executable Unix script cannot be found by which command
I have a Unix bash script written by a former teammate that must be in my PATH, though I can’t find it by manual inspection (see below). I can however execute it anywhere by just typing I would like to view and edit this script. However, when I try to find it via the which command, I get a blank
How can I control the number of running processes?
I’m doing a shell script and the unknown situation occurred. I must execute a certain number of processes, lets suppose 12. But I want to limit the executions by ‘t’ each time. So if ‘t’ is 3 I would have to execute 3 processes then 3, 3 and finally 3. But I would like to do it automatically, so I