All Questions
1,016 questions
1
vote
1
answer
64
views
Why can't I run an interactive command in awk in a pipeline?
Consider the following commands:
$ awk 'BEGIN { system("ed") }'
q
$ echo hello | awk 'BEGIN { system("ed") }'
?
$
In the first case, I was able run ed and then stay in the editor ...
- 3,422
0
votes
2
answers
91
views
Adding up sizes of directories using bash is inconsistent
First, I got the total size of folder /my-downloads:
$ du -sh /my-downloads
304G /my-downloads
As you can see, it's 304G.
Then, I wanted to find out the total size of all immediate directories ...
- 249
-1
votes
3
answers
111
views
filtering command output with awk
I want to extract the hostname (rd5044) from the output of a psql command like the below:
postgres@internal-rd5112:/opt/db/postgres/bin> psql -p 5434 -tc "SHOW primary_conninfo ;"
user=...
- 253
1
vote
4
answers
225
views
Trying to parse output of "lastb" command via awk, but when the userID field is blank, my variables are thrown off
I'm trying to pull the date and IP address from the output of lastb
I'm using: lastb | awk '{print $5,$6,$7,$3}'
The problem is that sometimes the first column (userID) of lastb is blank:
Data ...
- 183
2
votes
1
answer
455
views
Extract file path from Git diff output
I have the following command:
git diff branch1..branch2 | grep '^diff'
...that will output files that contains differences between two branches. Sample output is like this:
diff --git a/path-to-file1/...
- 237
2
votes
3
answers
434
views
Replace prefix string from lines in a file, and put into a bash array
In the file groupAfiles.txt are the lines:
file14
file2
file4
file9
I need a way to convert them to remove file and add /dev/loop and put them all in one line with a space between them.
/dev/loop14 /...
- 531
2
votes
1
answer
33
views
subset my .fam file using a .txt file of names
I have a .fam file in plink format, looks like this
1 I001.HO 0 0 1 1
2 I002.HO 0 0 1 1
3 IREJ-T006.HO 0 0 1 1
4 IREJ-T009.HO 0 0 1 1
5 IREJ-T022.HO 0 0 1 1
6 IREJ-T023.HO ...
- 23
2
votes
1
answer
186
views
Why does a 'pipe-to-awk' behave differently inside a function?
I'm using alsa to fiddle around with the volume on a Bluetooth speaker I have connected. It's a 1-speaker setup; just something to provide some background.
I can 'get' the volume setting fm the CLI as ...
- 3,727
0
votes
2
answers
103
views
Replace multiple lines in a file with another command
I can find all files in a directory with a particular name with find:
find . -name hello.mk
Inside each hello.mk I need to replace lines 9 and 10 with a single line, as shown below:
9: ...
- 123
1
vote
4
answers
130
views
BASH variable inside AWK that is itself an AWK command
I want to use a BASH variable inside AWK that is an AWK command. Here is my test code that I plan to make more complicated if I can find a solution to this problem.
exptransform=(
'print \"...
0
votes
4
answers
112
views
How to replace pattern in last line
I'm trying to replace "}," by "}" from the last line of a file :
My /etc/firefox/policies/policies.json file like this because I added the certificate lines using a for loop :
$ ...
- 2,401
1
vote
6
answers
668
views
Bash script that takes multiple path arguments and checks if files can be successfully created there
I would like a bash shell script (for my Debian 12 system) which accepts multiple paths as arguments, and then checks if a file can be successfully created in each one. Then the result should be put ...
- 293
-2
votes
4
answers
112
views
How to get either a substring or a text value using awk and if?
I can't figure out how to write a simple ping log. I only need either the ms value or the words "no connection".
I have myping=$(ping -c 1 10.0.10.1). I only need the value between "...
0
votes
2
answers
116
views
How to copy the value from one "column" to another in Bash?
I have a file with lines:
username="user1" email="[email protected]"
I need to take the username from the email address and replace the username value with it,
so the end result ...
-3
votes
1
answer
77
views
How to convert multiple columns to rows in shell (unpivoting)
I have a tab separated table with hundreds of columns and rows, like that:
OTUId AC0184 AC0250 AC0257 AC0258 AC0262 AC0263 AC0289 AC0293
OTU549024624 51659 0 0 0 0 0 0 0
OTU565712448 108 0 0 0 0 0 0 0 ...
