Questions tagged [shell]
The shell is Unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …). For shell scripts with errors, please check them in http://shellcheck.net before posting here.
12,267 questions
-4votes
0answers
51views
Creating in Linux files in GB or MB range by various random size by read a file [closed]
In Linux in Bash i have this script (thanks to Ed Morton) . $ cat ./tst.sh #!/usr/bin/env bash while read -r idx sfx size; do echo fallocate "file${idx}.${sfx}" "$size" done &...
- 533
-2votes
1answer
110views
Creating in Linux files in GB or MB range by various size by read a file [closed]
In Linux with Bash, there is the File numbers_in_one_line. In this file there is only one line with several numbers, all separated by spaces. These numbers are the value in bytes for creating files ...
- 533
9votes
3answers
784views
How to delete buffered text written to terminal during script execution
Let's say hypothetically I'm executing a long-running bash script, and while it's running, I accidentally right click on the terminal and paste a sensitive password (freshly copied out of a password ...
- 193
4votes
3answers
533views
Parse console output and audibly say error
I am testing testing app by running mycommand that outputs at the console and directly at /tmp/mycommand.log. Using zsh. mycommand is really a function with parameters, but I can get the same when ...
- 63
5votes
2answers
373views
How (internally) does fd3>&fd1 after { fd1>&fd3 } put back (or not) original fd into fd1? ("bad file descriptor")
`I'm reading an answer to https://stackoverflow.com/questions/692000/how-do-i-write-standard-error-to-a-file-while-using-tee-with-a-pipe/692009#692009, https://stackoverflow.com/a/14737103/5499118: { {...
- 1,247
0votes
1answer
103views
How to compare output of a program with a reference value in a shell script?
I have my own implementation of a Redis server which I'd like to test through a shell script. The general idea is to feed it with some commands through nc, and since nc prints the output of my program ...
- 111
4votes
1answer
164views
Run in background avoiding any job control message from the shell [duplicate]
Lets define a shell function (here the shell is Bash) and test it $ s () { xterm -e sleep 5 & } $ s [1] 307926 $ [1]+ Done xterm -e sleep 5 $ With my specific meaning of ...
- 1,336
9votes
2answers
1kviews
What is this icon (dots over a gray curving line) that momentarily appears in my GNOME status bar?
The leftmost icon () is the one in question. For context, I have a pair of multipoint Bluetooth earbuds simultaneously connected to both my iPhone and Linux laptop. When I'm listening to music on my ...
- 93
12votes
1answer
994views
Why doesn’t `sudo -E` preserve `PERL5LIB`?
I’m experiencing a strange behavior related to environment variable preservation with sudo on macOS(15.2): sudo -E doesn't preserve the environment variable PERL5LIB. Reproduction Steps Set an ...
0votes
2answers
97views
How to redirect output from a program that waits for input
Following this post I created my own version of the script, with the difference that user and password are forwarded from the environment variables: #!/bin/zsh pamtester login $user authenticate <&...
- 101
3votes
1answer
151views
Bash redirections - handling several filenames specially (man pages)
Please confirm/correct me. I've found related Duplication of file descriptors in redirection but that does not answer my specific question. From the The GNU Bash Reference Manual, section 3.6 ...
- 1,363
0votes
2answers
87views
how do i use pv in a script that has a seq for loop
I have a script that has a for loop in it that runs a specific amount of times, and I was wondering if it is possible to implement the pv command in my script to add a progress bar. Here is my code: ...
0votes
0answers
32views
Retry CLI tool for Linux [duplicate]
I often find myself needing something to retry commands that are 'likely' to fail for non-critical reasons and can just be reattempted a few times, such as periodic rsync jobs, metric collection/...
- 141
0votes
0answers
46views
Shell script not behaving as expected expanding variable as command [duplicate]
I am trying to script a job which interacts with mysql. I am using a variable to store a long command line. But when run via a script this does not behave as expected. I can reproduce the issue as ...
- 6,225
0votes
1answer
42views
What is (if any) the file descriptor of /dev/tty?
The urgent issue to read keyboard input in the pipeline is solved by the answer in https://stackoverflow.com/questions/15230289/read-keyboard-input-within-a-pipelined-read-loop: mycommand-outputpiped |...
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