The variable tag has no wiki summary.
2
votes
1answer
72 views
What does “${x%% *}” mean in sh? [duplicate]
I just saw "$${x%% *}" in a makefile, which means "${x%% *}" in sh.
Why it is written in this way ?
how can a makefile detect whether a command is available in the local machine?
determine_sum = \
...
0
votes
2answers
69 views
bash - reading user variable into bash script grep
I've tried every possible combination to get this bash script working. It's part of a larger script, and it basically prompts for a username (to check if it exists) and returns the appropriate ...
2
votes
2answers
57 views
List all my variables [duplicate]
I'm just learning the basics, including how to declare and mess around with variables. Is there a simple way to display a list of all the variables I've named? (Everything I've found by searching only ...
0
votes
1answer
48 views
How can I preserve new lines coming from a command's output during variable assignment?
Consider:
$ getfacl somefile.dat # The output is formatted and contains several new lines..
# file: somefile.dat
# owner: user1
# group: group1
user::rw-
group::r-- #effective:r--
...
1
vote
2answers
68 views
How to print shell variables and values to be able to copy/paste them?
In Bash 4.2.25, the set and env output is not escaped, so shell escapes and any non-printable characters won't be copy-pasteable. Take for example this shell session:
$ export foo=$'a\nbar=\baz'
$ ...
1
vote
1answer
60 views
What does mean ` AWK=@AWK@` in shell scripting
I found AWK=@AWK@ while reading sh script, it's something like AWK=$(which awk), but it's not working.
So can anyone explain this ?
Script :
#!/bin/sh -
# makelist.sh: Automatically generate header ...
1
vote
2answers
76 views
How do I set bash aliases and variables from within vim?
In cmdline mode, the following examples do not work for me.
!alias lol='echo lol'
!lol='echo lol'
2
votes
1answer
123 views
shell variable in awk is not being passed to all the lines but just for the very first line of input?
inputfile:is2.txt
10.39.5.41,A1,B1
10.39.5.41,A2,B2
10.39.5.41,A3,B3
10.39.5.41,A4,B4
10.39.5.41,A5,B5
10.39.5.41,A6,B6
script :
#!/bin/bash
second_column="OOOOOOO" # OOOOOOO will be added to ...
2
votes
2answers
81 views
Setting a shell variable in a null coalescing fashion
I'm really fond of "null coalescing", where you can set a variable to the first "non-null" value in a list of things. Many languages support this, for example:
C#:
String myStr = string1 ?? string2 ...
