shell - Bash regex =~ operator - Stack Overflow
Oct 18, 2013 · What is the operator =~ called? I'm not sure it has a name. The bash documentation just calls it the =~ operator. Is it only used to compare the right side against the left side? The right side is …
bash - What are the special dollar sign shell variables ... - Stack ...
Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process which …
bash - Shell equality operators (=, ==, -eq) - Stack Overflow
533 = and == are for string comparisons -eq is for numeric comparisons -eq is in the same family as -lt, -le, -gt, -ge, and -ne == is specific to bash (not present in sh (Bourne shell), ...). Using POSIX = is …
What's the difference between [ and [[ in Bash? - Stack Overflow
Make sure you have the #!/bin/bash shebang line for your script if you use double brackets. See also Bash FAQ - "What is the difference between test, [ and [ [ ?" Bash Practices - Bash Tests Server …
How to compare strings in Bash - Stack Overflow
Feb 10, 2010 · Bash always seemed backward with numeric evaluations using an operator consisting of a string (-eq) and string comparisons using a numeric operator "==" or "=" just you mess you up. If …
shell - What does "-ne" mean in bash? - Stack Overflow
Jul 17, 2013 · It doesn't mean anything "in bash". [ runs a command called test. -ne is an argument to the test command, not to bash, and you can find its documentation in man test.
What do the -n and -a options do in a bash if statement?
The switches -a and -n are not strictly part of a bash if statement in that the if command does not process these switches. What are primaries? I call them "switches", but the bash documentation that …
shell - Difference between sh and Bash - Stack Overflow
When writing shell programs, we often use /bin/sh and /bin/bash. I usually use bash, but I don't know what's the difference between them. What's the main difference between Bash and sh? What do we ...
Bash Script : what does #!/bin/bash mean? - Stack Overflow
Dec 14, 2012 · 21 In bash script, what does #!/bin/bash at the 1st line mean ? In Linux system, we have shell which interprets our UNIX commands. Now there are a number of shell in Unix system. Among …
bash - How do I use a regex in a shell script? - Stack Overflow
Mar 10, 2016 · Using Bash's own regex-matching operator, =~, is a faster alternative in this case, given that you're only matching a single value already stored in a variable: