93,020 questions
6278
votes
66
answers
5.2m
views
How do I execute a program or call a system command?
How do I call an external command within Python as if I had typed it in a shell or command prompt?
- 64.6k
4550
votes
35
answers
3.5m
views
How do I check if a directory exists or not in a Bash shell script?
What command checks if a directory exists or not within a Bash shell script?
- 130k
3657
votes
30
answers
3.4m
views
How to check if a string contains a substring in Bash
I have a string in Bash:
string="My string"
How can I test if it contains another string?
if [ $string ?? 'foo' ]; then
echo "It's there!"
fi
Where ?? is my unknown operator. ...
- 40.4k
3611
votes
31
answers
5.3m
views
How to concatenate string variables in Bash
In PHP, strings are concatenated together as follows:
$foo = "Hello";
$foo .= " World";
Here, $foo becomes "Hello World".
How is this accomplished in Bash?
- 68.3k
3594
votes
17
answers
3.9m
views
How do I copy a folder from remote to local using scp? [closed]
How do I copy a folder from remote to local host using scp?
I use ssh to log in to my server.
Then, I would like to copy the remote folder foo to local /home/user/Desktop.
How do I achieve this?
- 36.2k
3253
votes
19
answers
2.0m
views
What does " 2>&1 " mean?
To combine stderr and stdout into the stdout stream, we append this to a command:
2>&1
For example, the following command shows the first few errors from compiling main.cpp:
g++ main.cpp 2>&...
- 69.8k
3140
votes
19
answers
5.1m
views
How can I recursively find all files in current and subfolders based on wildcard matching?
How can I recursively find all files in current and subfolders based on wildcard matching?
- 36k
3032
votes
40
answers
3.9m
views
How do I split a string on a delimiter in Bash?
I have this string stored in a variable:
IN="[email protected];[email protected]"
Now I would like to split the strings by ; delimiter so that I have:
ADDR1="[email protected]"
ADDR2="[email protected]"
I don't ...
- 80.5k
2998
votes
17
answers
2.3m
views
How to mkdir only if a directory does not already exist?
I am writing a shell script to run under the KornShell (ksh) on AIX. I would like to use the mkdir command to create a directory. But the directory may already exist, in which case I do not want to do ...
- 37.7k
2517
votes
38
answers
2.5m
views
How to check if a variable is set in Bash
How do I know if a variable is set in Bash?
For example, how do I check if the user gave the first parameter to a function?
function a {
# if $1 is set ?
}
- 193k
2507
votes
16
answers
3.1m
views
How do I set a variable to the output of a command in Bash?
I have a pretty simple script that is something like the following:
#!/bin/bash
VAR1="$1"
MOREF='sudo run command against $VAR1 | grep name | cut -c7-'
echo $MOREF
When I run this script from the ...
- 25.5k
2418
votes
22
answers
2.3m
views
Loop through an array of strings in Bash?
I want to write a script that loops through 15 strings (array possibly?) Is that possible?
for databaseName in listOfNames
then
# Do something
end
- 43.2k
2416
votes
22
answers
2.7m
views
How can I delete all lines that contain a specific string from a text file?
How would I use sed to delete all lines in a text file that contain a specific string?
- 25.1k
2324
votes
51
answers
2.0m
views
How do I exclude a directory when using `find`? [closed]
How do I exclude a specific directory when searching for *.js files using find?
find . -name '*.js'
- 38k
2273
votes
21
answers
1.9m
views
How do I iterate over a range of numbers defined by variables in Bash?
How do I iterate over a range of numbers in Bash when the range is given by a variable?
I know I can do this (called "sequence expression" in the Bash documentation):
for i in {1..5}; do ...
- 23.6k