Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
How to ignore error in Bash script
Answer:
We have learned in the past on how to show the exit status of a given command.
But is it possible ignore the error and return normal exit code even the command has failed?
Yes, pipe "|| true" to the end of command, e.g.
# foo || true
-bash: foo: command not found
# echo $?
0As you can see even the command foo was not found, our last exit code is still zero.
Split on specific characters on Bash Script's for loop
Answer:
If you want to Bash script's for loop to split on non white-space characters, you can change the IFS, e.g.
#!/bin/bash
IFS='-'
list="a-b-c-d-e"
for c in $list; do
echo $c
doneThe above script will split on the character '-'
E.g.
# ./test.sh
a
b
c
d
e
Check if a file exist in Bash Shell
Answer:
The following script demonstrates how to check if a file exist, using shell (Bash) script
#!/bin/bash
if [ -e test.txt ]
then
echo 'The file exists.'
else
echo 'The file does not exist.'
fi
How to echo string to standard error (stderr)?
Answer:
To echo string to the standard error (stderr), rather than the standard output (stdout), you can define the following function in your shell (put in your ~/.bashrc file)
# function echo2() { echo "$@" 1>&2; }
Then you can execute the command like:
# echo2 test
Simple for loop in Bash shell
Answer:
A simple for loop in Bash shell would like the following. You can use it wisely to skip a lot of repetitive tasks.
#!/bin/bash
for i in {1..10}
do
echo "I am command No. $i"
done
