Random Unix Pieces

random_unix.sh

# find all lines not beginning with an #
cat somefile | grep -v "^#"

# split all lines to get only the part before the first #
cat somefile | cut -d'#' -f1

# remove all comments
cat somefile | grep -v "^#" | cut -d'#' -f1

# List all users
cat /etc/passwd | grep -v "^#" | cut -d':' -f1
awk -F":" '{print $1}' /etc/passwd | grep -v "^#"

# Remove all files in directory older than
find /path/to/directory/ -mindepth 1 -mtime +5 -delete

# List all groups
cat /etc/group | grep -v "^#" | cut -d':' -f1
awk -F":" '{print $1}' /etc/group | grep -v "^#"

# add aliases to system wide alias list
echo 'alias pmi "portmaster -ydbg --no-confirm"' >> /etc/csh.cshrc
echo 'alias pmn "echo ' ' && portmaster -L | grep New | cut -d: -f2 | tr -d ' '"' >> /etc/csh.cshrc