Questions tagged [shell]
The term 'shell' refers to a general class of text-based interactive command interpreters most often associated with the Unix & Linux operating systems. For questions about shell scripting, please use a more specific tag such as 'bash', 'powershell' or 'ksh'. Without a specific tag, a portable (POSIX-compliant) solution should be assumed, though using 'posix' in addition or 'sh' instead is preferable.
shell
92,868
questions
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votes
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answers
4.8m
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?
- 63.5k
4469
votes
35
answers
3.3m
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?
- 128k
3563
votes
30
answers
3.2m
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. ...
- 39.5k
3553
votes
31
answers
5.1m
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?
- 67.3k
3484
votes
17
answers
3.5m
views
How do I copy a folder or file from remote to local using scp?
How do I copy a folder or file 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 ...
- 35.1k
3183
votes
19
answers
1.8m
views
What does " 2>&1 " mean?
To combine stderr and stdout into the stdout stream, we append this to a command:
2>&1
e.g. to see the first few errors from compiling g++ main.cpp:
g++ main.cpp 2>&1 | head
What does ...
- 68.6k
3031
votes
19
answers
4.6m
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?
- 34.8k
2946
votes
39
answers
3.6m
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 ...
- 79k
2928
votes
17
answers
2.1m
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 ...
- 36.9k
2440
votes
38
answers
2.3m
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 ?
}
- 188k
2435
votes
16
answers
2.9m
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 ...
- 24.8k
2354
votes
21
answers
2.5m
views
How to delete from a text file, all lines that contain a specific string?
How would I use sed to delete all lines in a text file that contain a specific string?
- 24.5k
2304
votes
21
answers
2.1m
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?
Something like:
for databaseName in listOfNames
then
# Do something
end
- 41.7k
2219
votes
49
answers
1.8m
views
How do I exclude a directory when using `find`?
How do I exclude a specific directory when searching for *.js files using find?
find . -name '*.js'
- 36.6k
2218
votes
18
answers
1.7m
views
How to reload .bashrc settings without logging out and back in again?
If I make changes to .bashrc, how do I reload it without logging out and back in?
- 25.2k