After reading the Bash man pages and with respect to this post, I am still having trouble understanding what exactly the eval command does and which would be its typical uses. For example, if we do: $ set — one two three # Sets $1 $2 $3 $ echo $1 one $ n=1 $ echo … Read more
This question already has answers here: How to terminate a script? (12 answers) Closed 2 years ago. I have a simple Python script that I want to stop executing if a condition is met. For example: done = True if done: # quit/stop/exit else: # do other stuff Essentially, I am looking for something that … Read more
I have a file with about 1000 lines. I want the part of my file after the line which matches my grep statement. That is: cat file | grep ‘TERMINATE’ # It is found on line 534 So, I want the file from line 535 to line 1000 for further processing. How can I do … Read more
I want the variable sum/NR to be printed side-by-side in each iteration. How do we avoid awk from printing newline in each iteration ? In my code a newline is printed by default in each iteration for file in cg_c ep_c is_c tau xhpl printf “\n $file” >> to-plot.xls for f in 2.54 1.60 800 … Read more
I have written a Python script that checks a certain e-mail address and passes new e-mails to an external program. How can I get this script to execute 24/7, such as turning it into daemon or service in Linux. Would I also need a loop that never ends in the program, or can it be … Read more
I am trying to write a simple bash script that will copy the entire contents of a folder including hidden files and folders into another folder, but I want to exclude certain specific folders. How could I achieve this? 9 Answers 9
I am writing a nightly build script in bash. Everything is fine and dandy except for one little snag: #!/bin/bash for file in “$PATH_TO_SOMEWHERE”; do if [ -d $file ] then # do something directory-ish else if [ “$file” == “*.txt” ] # this is the snag then # do something txt-ish fi fi done; … Read more
I have noticed this in a couple of scripting languages, but in this example, I am using python. In many tutorials, they would start with #!/usr/bin/python3 on the first line. I don’t understand why we have this. Shouldn’t the operating system know it’s a python script (obviously it’s installed since you are making a reference … Read more
Currently I’m doing some unit tests which are executed from bash. Unit tests are initialized, executed and cleaned up in a bash script. This script usualy contains an init(), execute() and cleanup() functions. But they are not mandatory. I’d like to test if they are or are not defined. I did this previously by greping … Read more
I’ve seen Bash scripts test for a non-zero length string in two different ways. Most scripts use the -n option: #!/bin/bash # With the -n option if [ -n “$var” ]; then # Do something when var is non-zero length fi But the -n option isn’t really needed: # Without the -n option if [ … Read more
